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Molecules, Volume 5, Issue 3 (March 2000) – 160 articles , Pages 200-636

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Editorial

Jump to: Research

122 KiB  
Editorial
Proceedings of the 12th National Symposium of Organic Chemistry (XII SINAQO), Los Cocos, Cordoba, Argentina, 14-17 November 1999
by Claudio J. Salomon and Guillermo R. Labadie
Molecules 2000, 5(3), 252-282; https://doi.org/10.3390/50300252 - 22 Mar 2000
Cited by 1 | Viewed by 6356
Abstract
This Paper is downloadable at http://www.mdpi.org/molecules/papers/50300252.pdf Full article
12 KiB  
Editorial
Foreword to the Proceedings of the 12th National Symposium of Organic Chemistry "Dr. Eduardo Guerreiro", Los Cocos (Córdoba), Argentina, 14-17 November 1999
by Claudio J. Salomon and Guillermo R. Labadie
Molecules 2000, 5(3), 283-284; https://doi.org/10.3390/50300283 - 22 Mar 2000
Viewed by 4188
Abstract
n/a Full article

Research

Jump to: Editorial

36 KiB  
Article
Chemistry of Pyrones, Part 3: New Podands of 4H-Pyran-4-ones
by Aziz Shahrisa and Alireza Banaei
Molecules 2000, 5(3), 200-207; https://doi.org/10.3390/50300200 - 01 Mar 2000
Cited by 9 | Viewed by 5647
Abstract
New derivatives of 3,5-disubstituted 4H-Pyran-4-one podands (9-15) were prepared by transesterification reaction of dimethyl or diethyl 2,6-dimethyl-4H-pyran-4-one-3,5-dicarboxylate with some glycol, glycol ethers or by nucleophilic substitution of some phenols or glycol ethers with 3,5-bis (bromomethyl)-2,6-diphenyl-4H-pyran-4-one. Full article
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41 KiB  
Article
Synthesis of Some 2, 6-Disubstituted 4-Amidopyridines and -Thioamidopyridines, and Their Antimycobacterial and Photosynthesis-Inhibiting Activity
by Miroslav Miletin, Jiri Hartl, Martin Dolezal, Z. Odlerova, K. Kralova and Milos Machacek
Molecules 2000, 5(3), 208-218; https://doi.org/10.3390/50300208 - 03 Mar 2000
Cited by 15 | Viewed by 6686
Abstract
A group of 26 new 2-halogeno-6-alkylsulfanyl- and 2,6-bis-alkylsulfanyl-4-amidopyridines and corresponding thioamidopyridines was synthesised. Some of the amidopyridines and all thioamidopyridines were tested for their antimycobacterial activity against atypical mycobacterial strains. Promising photosynthesis-inhibiting activity was also found for some of the amidopyridines. Full article
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Scheme 1

60 KiB  
Article
Crystal Structure of Methyl 4-Acetamido-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-ß-D-allopyranoside
by Miroslav Koóš, Bohumil Steiner, Ján Gajdoš, Vratislav Langer, Dalma Gyepesová, L'ubomìr Smrčok and Marián Ďurík
Molecules 2000, 5(3), 219-226; https://doi.org/10.3390/50300219 - 02 Mar 2000
Cited by 5 | Viewed by 6185
Abstract
The detailed structure of methyl 4-acetamido-4-cyano-4,6-dideoxy-2,3-Oisopropylidene-ß-D-allopyranoside was established by X-ray analysis confirming allo configuration at C-4 and suggesting a 4C1 conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into the direction [...] Read more.
The detailed structure of methyl 4-acetamido-4-cyano-4,6-dideoxy-2,3-Oisopropylidene-ß-D-allopyranoside was established by X-ray analysis confirming allo configuration at C-4 and suggesting a 4C1 conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into the direction of 0H5, thus indicating a flattening at C-1 and C-4. Full article
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122 KiB  
Article
Design and Synthesis of a Conformationally Rigid Mimic of the Dihydropyrimidine Calcium Channel Modulator SQ 32,926
by Birgit Jauk, Tetiana Pernat and C. Oliver Kappe
Molecules 2000, 5(3), 227-239; https://doi.org/10.3390/50300227 - 03 Mar 2000
Cited by 126 | Viewed by 7218
Abstract
A conformationally rigid polyheterocycle (3) which mimics the putative receptorbound conformation of dihydropyridine-type calcium channel modulators is prepared in a seven-step reaction sequence based on a Biginelli-type cyclocondensation reaction. Full article
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26 KiB  
Article
DDQ/PbO2: a Novel Oxidation System for Hindered Electron Rich Benzhydrols
by G. P. Kalena, S. M. Jadhav and A. Banerji
Molecules 2000, 5(3), 240-244; https://doi.org/10.3390/50300240 - 14 Mar 2000
Cited by 10 | Viewed by 6614
Abstract
A convenient mild protocol for oxidation of highly hindered electron rich benzhydrols using DDQ / PbO2 has been developed. Full article
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Scheme 1

69 KiB  
Article
Heterocyclic Tricycles as Internal N-Glycosides from 2-Methyl-5-nitro-6-(2-nitrophenyl)-4-phenyl(2-furyl)tetrahydropyranols
by Lutz Götze, Manfred Michalik, Klaus Peseke, José Quincoces and Helmut Reinke
Molecules 2000, 5(3), 245-251; https://doi.org/10.3390/50300245 - 16 Mar 2000
Viewed by 5570
Abstract
1-Methyl-10-nitro-11-phenyl(2-furyl)-2-aza-13-oxa-tricyclo[7.3.1.03,8]trideca-3,5,7-trienes 3 were synthesized via the reduction of the aromatic 2-nitro group of 2-methyl-5-nitro-6-(2-nitrophenyl)-4-phenyl(2-furyl)tetrahydropyranols 2 and subsequent condensation with their anomeric OH group. As by-products, the corresponding 6-(2-aminophenyl)-2-methyl-5-nitro-4-phenyl(2-furyl)tetrahydropyranols 4 were isolated. Full article
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Figure 1

26 KiB  
Abstract
Plant Secondary Metabolites as Potential Anticancer Agents and Cancer Chemopreventives
by A. Douglas Kinghorn
Molecules 2000, 5(3), 285-288; https://doi.org/10.3390/50300285 - 22 Mar 2000
Cited by 14 | Viewed by 3959
Abstract
n/a Full article
9 KiB  
Abstract
Experimental and Theoretical studies on the Mechanism of Grignard Reagent Formation
by M. Chanon
Molecules 2000, 5(3), 289; https://doi.org/10.3390/50300289 - 22 Mar 2000
Cited by 3 | Viewed by 3976
Abstract
n/a Full article
23 KiB  
Abstract
Enzymes in Organic Solvents: the Use of Lipases and (R)-Oxynitrilase for the Preparation of Products of Biological Interest
by Vicente Gotor
Molecules 2000, 5(3), 290-292; https://doi.org/10.3390/50300290 - 22 Mar 2000
Cited by 3 | Viewed by 6812
Abstract
The use of enzymes in organic solvents has acquired a special relevance in organic synthesis, and lipases are the enzymes most commonly used in transesterication reactions. In the past few years, we have shown the utility of enzymatic aminolysis and ammonolysis reactions for [...] Read more.
The use of enzymes in organic solvents has acquired a special relevance in organic synthesis, and lipases are the enzymes most commonly used in transesterication reactions. In the past few years, we have shown the utility of enzymatic aminolysis and ammonolysis reactions for the preparation of amides and for the resolution of esters and amines. The enzymatic alkoxycarbonylation reaction is of great utility in chemoselective reactions of natural products. Lipases, enzymes much less exploited in organic synthesis, have an increasing interest, especially the use of (R)-oxynitrilases for the synthesis of optically active cyanohydrins. Full article
56 KiB  
Abstract
Aziridine Carboxylates, Carboxamides and Lactones: New Methods for Their Preparation and Their Transformation into α- and β-Amino Acid Derivatives
by Robert H. Dodd
Molecules 2000, 5(3), 293-298; https://doi.org/10.3390/50300293 - 22 Mar 2000
Cited by 18 | Viewed by 8401
Abstract
The preparation of a variety of novel aziridine-γ-lactones (3) from carbohydrates is described. In contrast to aziridine-2-carboxylates, the lactones react regiospecifically at C-2 with soft nucleophiles to provide optically pure substituted β-amino acid precursors. Hard nucleophiles react exclusively at the C-3 position to [...] Read more.
The preparation of a variety of novel aziridine-γ-lactones (3) from carbohydrates is described. In contrast to aziridine-2-carboxylates, the lactones react regiospecifically at C-2 with soft nucleophiles to provide optically pure substituted β-amino acid precursors. Hard nucleophiles react exclusively at the C-3 position to provide α-amino acid precursors. The utility of this methodology was demonstrated by the preparation of (3S,4S)-dihydroxy-L-glutamic acid (DHGA) from the appropriate aziridine-γ-lactone. DHGA was subsequently shown to be a selective partial agonist of mGluR1 receptors. A more concise preparation of aziridine-γ-lactones was achieved by 1,4-Michael addition of benzylamine to 2-O-triflylbutenolides. Use of a 2-O-mesylbutenolide led, under the same conditions, to the corresponding aziridine-2-carboxamides or 2-carboxylates. Finally, a new Evanstype aziridinating agent, Ses-iminoiodinane, was developed and shown to react efficiently with unsaturated substrates to give the corresponding aziridines, whose N-Ses protecting groups can be removed under mild conditions. Full article
21 KiB  
Abstract
Targeting DNA with Anthracyclines: The Importance of the Sugar Moiety
by Waldemar Priebe
Molecules 2000, 5(3), 299-301; https://doi.org/10.3390/50300299 - 22 Mar 2000
Cited by 15 | Viewed by 3975
Abstract
n/a Full article
15 KiB  
Abstract
Chemistry of the Calceolaria Genus. Structural and Biological Aspects
by Juan A. Garbarino, María C. Chamy and Marisa Piovano
Molecules 2000, 5(3), 302-303; https://doi.org/10.3390/50300302 - 22 Mar 2000
Cited by 17 | Viewed by 6422
Abstract
Autochthonous species of the Calceolaria (Scrophulariaceae) genus are studied. From their apolar extracts 55 new diterpenes of six skeleton types, naphtoquinones and flavonoids have been isolated. Among the different diterpenes malonic substitutions and bis-diterpenes in which both units are joined by a malonic [...] Read more.
Autochthonous species of the Calceolaria (Scrophulariaceae) genus are studied. From their apolar extracts 55 new diterpenes of six skeleton types, naphtoquinones and flavonoids have been isolated. Among the different diterpenes malonic substitutions and bis-diterpenes in which both units are joined by a malonic acid unit stand out. Pimaranes present C-9 epimerisation and, consequently, H-9 has the same orientation as Me-20. From C.sessilis naphthoquinones with antichagasic activity have been isolated; and the biotransformation of 2α,19-dihydroxy-9-epi-entpimara-7,15-diene with Giberella fujikuroi produced 7 new diterpenes. Full article
21 KiB  
Abstract
Synthesis of Polymers with Electro-optical Properties
by R. O. Garay
Molecules 2000, 5(3), 304-306; https://doi.org/10.3390/50300304 - 22 Mar 2000
Cited by 2 | Viewed by 3819
Abstract
n/a Full article
16 KiB  
Abstract
Mechanisms of Water Catalysed Reactions
by Eduardo Humeres
Molecules 2000, 5(3), 307-308; https://doi.org/10.3390/50300307 - 22 Mar 2000
Cited by 1 | Viewed by 3330
Abstract
n/a Full article
15 KiB  
Abstract
N-Alkyl-N-methylacetamidinium Ions. Isomerization and Water Catalyzed Exchange Rates in D2O
by Angel Dacosta, Sarah V. Pekerar and Oswaldo Núñez
Molecules 2000, 5(3), 309-310; https://doi.org/10.3390/50300309 - 22 Mar 2000
Cited by 2 | Viewed by 3767
Abstract
n/a Full article
15 KiB  
Abstract
Natural Inhibitors of the Aromatase Enzyme
by Roberto R. Gil
Molecules 2000, 5(3), 311-312; https://doi.org/10.3390/50300311 - 22 Mar 2000
Viewed by 5102
Abstract
The results of three years of search for natural aromatase inhibitors will be presented. Full article
15 KiB  
Abstract
Synthesis of New Anthihelmintic Analogs of Marine Natural Products
by Gloria Serra, Graciela Mahler, Sandra Gordon, Marcelo Incerti and Eduardo Manta
Molecules 2000, 5(3), 313-314; https://doi.org/10.3390/50300313 - 22 Mar 2000
Viewed by 5675
Abstract
The synthesis of new anthelmintic compounds derived from 2-amine-4-hydroxy-δ-valerolactams and 2,4-dialkylthiazoles is described. The synthetic procedures and biological activity data for these compounds will be presented. Full article
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Scheme 1

15 KiB  
Abstract
Synthesis of Derivatives of Biogenic Amines Labelled with Radioactive Tracers for Brain Imaging
by Arturo A. Vitale
Molecules 2000, 5(3), 315-316; https://doi.org/10.3390/50300315 - 22 Mar 2000
Viewed by 5110
Abstract
Endogenous derivatives of biogenic amines, such as phenethylamines, indolalkylamines and harmines, have been extensively studied as usual constituents of body fluids. Methylated derivatives of indolalkylamines have been also related to mental disorders, e.g. schizophrenia and hallucination. Full article
15 KiB  
Abstract
Role of Weak Molecular Interactions in the Mechanism of Action of a Series of Antihelmintics
by Marisa Santo, Liliana Giacomelli, Mario Reta, Rosa Cattana, Juana Silber, Antonio Chana, Mercedes Rodriguez and Carmen Ochoa
Molecules 2000, 5(3), 317-318; https://doi.org/10.3390/50300317 - 22 Mar 2000
Cited by 3 | Viewed by 6352
Abstract
Different physicochemical properties such as solute-solute and solute-solvent interactions, tautomerism, lipophilicity and solubility in water were determined for a serie of 6,7-diaryl-pteridines in order to relate those properties with their nematocide action. Full article
17 KiB  
Abstract
The AlCl3–L Reagent and its Application to the Regioselective Carbon–Carbon Bond Formation
by Alejandra G. Suárez
Molecules 2000, 5(3), 319-320; https://doi.org/10.3390/50300319 - 22 Mar 2000
Cited by 1 | Viewed by 6594
Abstract
Use of the AlCl3–L reagent in the regioselective acylation of benzodioxinic derivatives. Spectroscopic studies show the presence of coordination compounds as reaction intermediates, being the responsible of the observed regioselectivity. Full article
17 KiB  
Abstract
A Short Synthesis of the Main Lactone Ketal Backbone Present in Saudin
by Guillermo R. Labadie, Raquel M. Cravero and Manuel Gonzalez Sierra
Molecules 2000, 5(3), 321-322; https://doi.org/10.3390/50300321 - 22 Mar 2000
Cited by 9 | Viewed by 5570
Abstract
We are describing a brief stereospecific synthesis of a model compound related to Saudin, with a lactone ketal backbone present in the natural product starting from a tricyclic epoxiketal. Full article
15 KiB  
Abstract
Using Empirical Rules from 13C NMR Analysis to Determine the Stereochemistry of the Epoxide Located at the 5,6-position of Decalinic Systems
by Raquel M. Cravero, Guillermo R. Labadie and Manuel Gonzalez Sierra
Molecules 2000, 5(3), 323-324; https://doi.org/10.3390/50300323 - 22 Mar 2000
Cited by 2 | Viewed by 5574
Abstract
An empiric rule derived from the analysis of the 13C NMR spectral data, allowed us to determine 5,6-epoxide stereochemistry on decalinic systems and a discussion of the scope and limitations of this rule and its extension to other carbon squeletons, is presented. Full article
16 KiB  
Abstract
Biotransformation of Ilicic Alcohol with Aspergillus Niger
by Leticia Pous, Roberto Carrizo, Marcela Kurina Sanz, José C. Gianello and Eduardo Guerreiro
Molecules 2000, 5(3), 325-326; https://doi.org/10.3390/50300325 - 22 Mar 2000
Cited by 3 | Viewed by 4327
Abstract
3β-hidroxyilicic alcohol was obtained from of ilicic alcohol using cultures of Aspergillus niger. Full article
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Figure 1

20 KiB  
Abstract
Applications of Olefination Reactions to Cassiol Synthesis
by María I. Colombo, Jose A. Bacigaluppo, Mirta P. Mischne, Juán Zinczuk and Edmundo A. Rúveda
Molecules 2000, 5(3), 327-329; https://doi.org/10.3390/50300327 - 22 Mar 2000
Viewed by 5447
Abstract
Olefination reactions directed to the synthesis of cassiol from compounds 2-5 will be discussed. Full article
16 KiB  
Abstract
New Anti-Neoplastics Obtained by a Molecular Connectivity Method
by S. Villagra, E. Jáuregui and J. Gálvez
Molecules 2000, 5(3), 330-331; https://doi.org/10.3390/50300330 - 22 Mar 2000
Cited by 2 | Viewed by 6704
Abstract
Molecular Connectivity is a method, which allows to discriminate different pharmacological activities on the basics of numeric parameters of the molecules in study, related with specific and exclusive indexes. In the present study, we propose two potentially anti-neoplasic compounds: tricromil and zomepirac, [...] Read more.
Molecular Connectivity is a method, which allows to discriminate different pharmacological activities on the basics of numeric parameters of the molecules in study, related with specific and exclusive indexes. In the present study, we propose two potentially anti-neoplasic compounds: tricromil and zomepirac, by analyzing more than a hundred different chemicals. Full article
15 KiB  
Abstract
Octyl Phenol Synthesis Using Natural Clays
by S. Casuscelli, E. Herrero, J. Fernandez and M. Piqueras
Molecules 2000, 5(3), 332-333; https://doi.org/10.3390/50300332 - 22 Mar 2000
Viewed by 6876
Abstract
A series of clay minerals, HB, NB and Al-PILC have been studied in the alkylation reactions of 2-octanol with phenol at 180°C, under conditions of alcohol/phenol = 1 (mole ratio) and W/FAo °= 64,27 ghmol-1. The selectivity of Al-PILC was 77,12% [...] Read more.
A series of clay minerals, HB, NB and Al-PILC have been studied in the alkylation reactions of 2-octanol with phenol at 180°C, under conditions of alcohol/phenol = 1 (mole ratio) and W/FAo °= 64,27 ghmol-1. The selectivity of Al-PILC was 77,12% for octyl phenol and 16,5% for dioctyl phenol. Full article
21 KiB  
Abstract
Total Synthesis of Marchantinquinone
by V. López, E. Pandolfi and G. Seoane
Molecules 2000, 5(3), 334-335; https://doi.org/10.3390/50300334 - 22 Mar 2000
Cited by 1 | Viewed by 6351
Abstract
During the last years, many bisbibenzylic macrocyclic ethers were isolated and identified in Hepaticae. One of them is MARCHANTINQUINONE, a quinonic macrocycle with interesting biological activity. In the following report, we present the last steps of the total synthesis. Full article
16 KiB  
Abstract
Catalytic Epoxidation of Limonene
by E. Herrero, S. Casuscelli, J. Fernandez, C. Poncio, M. Rueda and O. Oyola
Molecules 2000, 5(3), 336-337; https://doi.org/10.3390/50300336 - 22 Mar 2000
Cited by 9 | Viewed by 5481
Abstract
The epoxidation of limonene with hidrogen peroxide was studied over zeolite Tibeta (a large pore material) and heteropoly acids on carbono and alumina supported. PW11/C was catalyst the best tested. Full article
18 KiB  
Abstract
Base-Catalyzed Formation of Imidazole Derivatives
by A. N. Vasiliev, A. F. López and A. J. Mocchi
Molecules 2000, 5(3), 338-339; https://doi.org/10.3390/50300338 - 22 Mar 2000
Cited by 1 | Viewed by 4498
Abstract
n/a Full article
16 KiB  
Abstract
Organic Cosolvent Effect on the Estimation of the Solubility of Oil Residues in Soil
by S. Ríos, O. Katusich and N. Nudelman
Molecules 2000, 5(3), 340-341; https://doi.org/10.3390/50300340 - 22 Mar 2000
Cited by 2 | Viewed by 7070
Abstract
The solubility in water and the partition coefficients, K, in soils samples of residues of petroleum of different ages were determined using an organic cosolvent (methanol), and the solvophobic theory was applied for the interpretation of results. The behavior of the residuals turned [...] Read more.
The solubility in water and the partition coefficients, K, in soils samples of residues of petroleum of different ages were determined using an organic cosolvent (methanol), and the solvophobic theory was applied for the interpretation of results. The behavior of the residuals turned out to be dependent of the cosolvent fraction. The values of K’s vary among 900 (Lkg-1) and 2,900 (Lkg-1) showing a general and marked increase for residues of increasing age. The determined parameters are useful for the modeling of environmental impact in polluted soils. Full article
19 KiB  
Abstract
Preparation and Characterization of Solid Complexes of Naphtoquinone and Hydroxypropyl-b-Cyclodextrin
by Marcela Linares, María Martínez De Bertorello and Marcela Longhi
Molecules 2000, 5(3), 342-344; https://doi.org/10.3390/50300342 - 22 Mar 2000
Cited by 4 | Viewed by 6164
Abstract
The formation of an inclusion compound between a naphthoquinone derivative (I) and HP-ß-CD was studied in solid state by X-ray diffractometry, DSC, and IR. Full article
20 KiB  
Abstract
Macrocyclic Trichothecene Production by the Fungus Epibiont of Baccharis Coridifolia
by M. L. Rosso, M. S. Maier and M. D. Bertoni
Molecules 2000, 5(3), 345-347; https://doi.org/10.3390/50300345 - 22 Mar 2000
Cited by 4 | Viewed by 5904
Abstract
Cultures of the fungus epibiont from the herbaceous shrub B. coridifolia yielded four macrocyclic trichothecenes. As these toxins are the same as those found in B. coridifolia, the relationship between the plant and the epibiont must be considered as mutualistic. Full article
18 KiB  
Abstract
Sulfated Polyhydroxysteroids from the Antartic Ophiuroid Gorgonocephalus Chilensis
by M. S. Maier, E. Araya and A. M. Seldes
Molecules 2000, 5(3), 348-349; https://doi.org/10.3390/50300348 - 22 Mar 2000
Cited by 3 | Viewed by 5485
Abstract
Five disulfated steroids and a mixture of monosulfated steroids were isolated from the ethanolic extract of the antarctic ophiuroid Gorgonocephalus chilensis. The structures were determined by 1H-NMR, 13C-NMR and FABMS. Full article
18 KiB  
Abstract
Labidiasteroside A, a Novel Saponin from the Antartic Starfish Labidiaster Annulatus
by M. E. Díaz de Vivar, M. S. Maier and A. M. Seldes
Molecules 2000, 5(3), 350-351; https://doi.org/10.3390/50300350 - 22 Mar 2000
Cited by 2 | Viewed by 6771
Abstract
Purification of the ethanolic extract of the starfish L. annulatus led to the isolation of two sulfated glycosides and a pentahydroxylated steroid. One of the saponins contains a novel pentasaccharide chain attached to C-6 of the steroidal aglycone. Full article
14 KiB  
Abstract
Bioactive Steroidal Glycosides from the Starfish Anasterias Minuta
by H. Chludil, M. S. Maier and A. M. Seldes
Molecules 2000, 5(3), 352-353; https://doi.org/10.3390/50300352 - 22 Mar 2000
Viewed by 5053
Abstract
Cytotoxic fractions obtained by purification of the ethanolic extract of Anasterias minuta contain sulfated hexasaccharide glycosides. These compounds show antifungal activity against Cladosporium cucumerinum. Full article
15 KiB  
Abstract
Bioactive Metabolites Produced by Fungi Cultures
by L. M. Levy, G. M. Cabrera, Jorge E. Wright and A. M. Seldes
Molecules 2000, 5(3), 354-355; https://doi.org/10.3390/50300354 - 22 Mar 2000
Cited by 4 | Viewed by 5383
Abstract
A screening of metabolites guided by antimicrobial and citotoxic bioassays was conducted with several fungi. The bioactive compounds were isolated and identified from the active extracts. Full article
16 KiB  
Abstract
Microbial Hydroxylation of Tedonodiol with Cultures of Aspergillus Niger
by R. Carrizo Flores, L. Pous, C. E. Tonn, E. Guerreiro and O. S. Giordano
Molecules 2000, 5(3), 356-357; https://doi.org/10.3390/50300356 - 22 Mar 2000
Cited by 1 | Viewed by 5186
Abstract
Microbial hydroxylation of tedonodiol, an eremophilane alcohol, was carried out with Aspergillus niger cultures, yielding the 2α - hydroxyderivative. Full article
13 KiB  
Abstract
Synthesis and Physicochemical Study of a Quinoxaline Derivative with Potencial Antineoplasic or Anti-HIV Activity
by Gabriela A. Rodrigo, Diana G. Bekerman, Adriana E. Robinsohn and Beatriz M. Fernández
Molecules 2000, 5(3), 358-359; https://doi.org/10.3390/50300358 - 22 Mar 2000
Cited by 2 | Viewed by 7845
Abstract
Kinetics of the synthesis of 3-[3-quinoxaline(1H)-one]propionic acid (I) were performed. This compound was achieved from reaction between o-phenylenediamine and α-ketoglutaric acid under different experimental conditions, and it was sent to the National Cancer Institute (USA) for its pharmacological evaluation. Full article
15 KiB  
Abstract
Effect of Substituents on the O-O Bond Rupture of Different Organic Peroxides in Toluene Solution
by G. N. Eyler, A. I. Cañizo, C. M. Mateo, E. E. Alvarez and R. K. Nesprías
Molecules 2000, 5(3), 360-361; https://doi.org/10.3390/50300360 - 22 Mar 2000
Cited by 1 | Viewed by 5709
Abstract
The thermal decomposition reaction of cyclic organic peroxides was studied in toluene solution in a wide temperature range. The kinetic data show an important substituent effect on the unimolecular homolysis of the O-O bond of these molecules. Full article
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Figure 1

16 KiB  
Abstract
Thermal Decomposition Reaction of cis-6-Phenyl-5,6-(2-phenylpropilydene)-3,3-tetramethylene-1,2,4-trioxacyclohexane in Different Solvents
by L. F. R. Cafferata, G. N. Eyler, A. I. Cañizo, C. M. Mateo and R. S. Rimada
Molecules 2000, 5(3), 362-364; https://doi.org/10.3390/50300362 - 22 Mar 2000
Cited by 1 | Viewed by 6460
Abstract
The kinetics of the thermal decomposition reaction of cis-6-phenyl-5,6-(2-phenyl-propilydene)-3,3-tetramethylene-1,2,4-trioxacyclohexane (I) was investigated in the temperature range of 100-130°C in selected solvents of different physicochemical properties to evaluate a solvent effect on the reaction. Full article
15 KiB  
Abstract
Thermal Decomposition Reaction of Acetophenone Cyclic Diperoxide in Solvents of Different Physicochemical Properties
by C. M. Mateo, A. I. Cañizo and G. N. Eyler
Molecules 2000, 5(3), 365-366; https://doi.org/10.3390/50300365 - 22 Mar 2000
Cited by 1 | Viewed by 6426
Abstract
The thermal decomposition reaction of acetophenone cyclic diperoxide (trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetroxane; APDP) at the initial concentration of c.a. 0.01 mol kg-1 and temperature ranges of 135.5 to 185.0° C has been investigated in dioxane and acetonitrile solutions, and in an 2-propanol/benzene mixture. Full article
30 KiB  
Abstract
Synthesis and Bioactivity of Teasterone and Typhasterol Analogs
by Javier A. Ramírez, Romina Mancusso, Silvina Sarno and Lydia R. Galagovsky
Molecules 2000, 5(3), 367-369; https://doi.org/10.3390/50300367 - 22 Mar 2000
Cited by 3 | Viewed by 5029
Abstract
Four brassinosteroids analogs of homoteasterone and homotyphasterol bearing 5α-OH and 5α-F groups have been synthesized and their bioactivities evaluated. Full article
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Scheme 1

16 KiB  
Abstract
Chemo- and Stereoselective Reduction of Polyfunctional Carbonyl Compounds by Mucor rouxii
by Constanza P. Mangone, Elba N. Pereyra, Silvia M. Moreno de Colonna and Alicia Baldessari
Molecules 2000, 5(3), 370-371; https://doi.org/10.3390/50300370 - 22 Mar 2000
Cited by 1 | Viewed by 5303
Abstract
Several polyfunctional carbonyl compounds, such as α- and β-ketoesters, were chemo- and stereoselectively reduced by Mucor rouxii cultures in water and in organic solvents. Results show that reductions can be carried out in a variety of organic solvents. Full article
17 KiB  
Abstract
Lipase-Catalyzed Polymerization of Glycerol and Dicarboxylic Acids in an Organic Medium
by Romina C. Pessagno and Alicia Baldessari
Molecules 2000, 5(3), 372-373; https://doi.org/10.3390/50300372 - 22 Mar 2000
Cited by 1 | Viewed by 4896
Abstract
Lipases from different sources catalyze the polyesterification of glycerol and several dicarboxylic acids in presence or organic solvents Full article
16 KiB  
Abstract
Electrosynthesis of 3-Nitrophenotiazine. Nitration in Non-Aqueous Solutions
by P. A. Perlo, M. N. Cortona, J. J. Silber and L. E. Sereno
Molecules 2000, 5(3), 374-375; https://doi.org/10.3390/50300374 - 22 Mar 2000
Cited by 1 | Viewed by 5988
Abstract
The nitration of Phenothiazine (PHEN) in acetonitrile (ACN) in the presence of excess NaNO2 has been studied in detail. First, the electrochemical behavior of the reactants was investigated by cyclic voltammetry to determine the electrolysis conditions. Controlledpotential electrolysis was used for the [...] Read more.
The nitration of Phenothiazine (PHEN) in acetonitrile (ACN) in the presence of excess NaNO2 has been studied in detail. First, the electrochemical behavior of the reactants was investigated by cyclic voltammetry to determine the electrolysis conditions. Controlledpotential electrolysis was used for the electrosynthesis. Full article
18 KiB  
Abstract
Chemical Characteristics of Passiflora Caerulea Sedd Oil and Residual Seed Meal
by O. E. Quiroga, S. Bou, M. S. Vigo and S. M. Nolasco
Molecules 2000, 5(3), 376-378; https://doi.org/10.3390/50300376 - 22 Mar 2000
Cited by 4 | Viewed by 6750
Abstract
Seeds from Passiflora caerulea were defatted with n-hexane yielding 29,9% of crude oil (dry basis). The crude oil was examined in their physicochemical characteristics. Fatty acid composition value showed only three acids in significative proportion: 16:0, 18:1 and 18:2. The residual seed meal [...] Read more.
Seeds from Passiflora caerulea were defatted with n-hexane yielding 29,9% of crude oil (dry basis). The crude oil was examined in their physicochemical characteristics. Fatty acid composition value showed only three acids in significative proportion: 16:0, 18:1 and 18:2. The residual seed meal analysis included: moisture value, ash, metals content, sugars, crude fiber, protein and available lysine. Full article
16 KiB  
Abstract
Photodynamic Effect Of 5,10,15,20-Tetrakis(4-Methoxyphenyl) Porphine (TMP) on Hep-2 Cell Lines
by M. G. Alvarez, E. I. Yslas, V. Rivarola, G. Mori, M. La Penna, J. J. Silber and E. N. Durantini
Molecules 2000, 5(3), 379-380; https://doi.org/10.3390/50300379 - 22 Mar 2000
Cited by 10 | Viewed by 6410
Abstract
The photodynamic effect of 5,10,15,20-tetrakis(4-methoxyphenyl)porphine (TMP) on Hep-2 cell line is reported. The incorporation of TMP was analyzed at different times and photosensitizer concentrations. The irradiation of cell cultures produces cell mortality, while no toxicity was observed in dark condition. Full article
14 KiB  
Abstract
Synthesis and Characterization of Some N-Heterocyclic Carbohydrate Derivatives
by M. A. Martins Alho and N. B. D’Accorso
Molecules 2000, 5(3), 381-382; https://doi.org/10.3390/50300381 - 22 Mar 2000
Viewed by 5966
Abstract
The nucleophilic bimolecular substitution on 1,2:3,4-di-O-isopropylidene-α-Dgalactopyranose with NH2-heterocyclic derivatives allows us to obtain some new compounds with potential biological activities. The characterization of them as well as a discussion of their reactivities toward sulfur analogues are present. Full article
21 KiB  
Abstract
Synthesis and Characterization of Bent-rod Liquid Crystals
by Pablo Del Rosso, Sandra A. Hernandez and Raúl O. Garay
Molecules 2000, 5(3), 383-385; https://doi.org/10.3390/50300383 - 22 Mar 2000
Viewed by 5780
Abstract
Two series of diesters with bend-rod shapes were synthesized and their thermal properties characterized by POM and DSC. The central group conformational mobility and polarity as well as the length of the mesogenic groups were varied in order to correlate these parameters with [...] Read more.
Two series of diesters with bend-rod shapes were synthesized and their thermal properties characterized by POM and DSC. The central group conformational mobility and polarity as well as the length of the mesogenic groups were varied in order to correlate these parameters with mesophase stability. Results indicate that series II diesters are enantiotropic and that their mesophase sensitivity to central group structural changes is limited. Full article
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Scheme 1

17 KiB  
Abstract
Two New Labdane Diterpene Glycoside from Flowers of Bacchris Medulosa DC
by D. A. Cifuente, C. E. Tonn and O. S. Giordano
Molecules 2000, 5(3), 386-387; https://doi.org/10.3390/50300386 - 22 Mar 2000
Cited by 1 | Viewed by 5135
Abstract
Two new labdane-type diterpene glycoside, were isolated from the flowers of Baccharis medulosa DC (Asteraceae). Structures of these compounds were established by application of various spectroscopic techniques. Full article
18 KiB  
Abstract
Reactivity of β-Stannylketones. Elimination vs. Substitution
by Ana Paula Murray and Alicia B. Chopa
Molecules 2000, 5(3), 388-390; https://doi.org/10.3390/50300388 - 22 Mar 2000
Viewed by 5128
Abstract
In the present work we report the results obtained in the reaction of β-stannylketones (I) with t-BuONa in dimethylsulfoxide (DMSO) and acetonitrile (ACN) as solvents. The reaction mechanisms probably involved are proposed. Full article
18 KiB  
Abstract
Addition of Organotin Anions to α,β-Unsaturated Nitriles
by V. Lassalle, M. T. Lockhart and A. B. Chopa
Molecules 2000, 5(3), 391-392; https://doi.org/10.3390/50300391 - 22 Mar 2000
Viewed by 5281
Abstract
The addition reaction of triorganotin anions to α,β-unsaturated nitriles leads to α-alkyl-β-stannylnitriles with high diastereoselectivity. Full article
20 KiB  
Abstract
N,N-Diethyl-1-Tosyl-3-Indoleglyoxylamide as a Dienophile in Diels-Alder Reactions. Hyperbaric vs. Thermal Conditions
by B. Biolatto, M. Kneeteman and P. M. Mancini
Molecules 2000, 5(3), 393-395; https://doi.org/10.3390/50300393 - 22 Mar 2000
Cited by 3 | Viewed by 5622
Abstract
Under high pressure conditions, the Diels-Alder reaction involving N,N-diethyl-1-tosyl-3-indoleglyoxylamide and 1-(N-acetyl-N-propylamino)-1,3-butadiene produces a highly functionalized intermediate for the synthesis of Indole Alkaloids, in shorter times and higher yields than under thermal conditions. Full article
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Scheme 1

19 KiB  
Abstract
Synthesis of Poly(m-pyridylene-1,2-diphenylvinylene)
by Rosana S. Montani, Alejandra S. Diez and Raúl O. Garay
Molecules 2000, 5(3), 396-397; https://doi.org/10.3390/50300395 - 22 Mar 2000
Cited by 1 | Viewed by 5707
Abstract
The synthesis by dehalogenating polycondensation and characterization of a new soluble conjugated polymer, poly(m-pyridylene-1,2-diphenylvinylene), DP-PPyV, is reported here. It shows good mechanical properties and a λmax = 330 nm. The maximum intensity peak of MALDI-TOF corresponds to 1.800 Da. Full article
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Scheme 1

21 KiB  
Abstract
Structure-Fluorescence Relationships in Antimicrobial Fluoroquinolones (AMFQs)
by Ana P. Vilches, Marcelo J. Nieto, María R. Mazzieri and Ruben H. Manzo
Molecules 2000, 5(3), 398-400; https://doi.org/10.3390/50300398 - 22 Mar 2000
Cited by 5 | Viewed by 5534
Abstract
The analysis of fluorescence spectra of a set of structurally related AMFQ let to identify the effects of structural changes and the presence of electric charge generated by acid-base reaction on the emission spectra. Full article
16 KiB  
Abstract
Reaction of 2,4-Dinitrochlorobenzene with Aromatic Amines in Toluene: Effect of Nucleophile Structure
by C. E.S. Alvaro, M. C. Savini, V. Nicotra, J. S. Yankelevich and N. S. Nudelman
Molecules 2000, 5(3), 401-402; https://doi.org/10.3390/50300401 - 22 Mar 2000
Cited by 5 | Viewed by 7922
Abstract
The kinetics of the reaction of 2,4-dinitrochlorobenzene (DNClB) with aniline and substituted anilines such as p-anisidine, p-toluidine and N-methylaniline have been studied in toluene. Except for N-methylaniline the reactions have shown a third order in amine rate dependence which is consistent with aggregates [...] Read more.
The kinetics of the reaction of 2,4-dinitrochlorobenzene (DNClB) with aniline and substituted anilines such as p-anisidine, p-toluidine and N-methylaniline have been studied in toluene. Except for N-methylaniline the reactions have shown a third order in amine rate dependence which is consistent with aggregates of the amine acting as the nucleophile. On the other hand, the reaction of DNClB with N-methylaniline under the same conditions shows a linear dependence of the second order rate coefficient, kA, vs [amine], which is consistent with the previous mechanism. Full article
16 KiB  
Abstract
1-Nitronaphtalene as a Dienophile in Diels-Alder Reactions
by E. Paredes, B. Biolatto, M. Kneeteman and P. M. Mancini
Molecules 2000, 5(3), 403-404; https://doi.org/10.3390/50300403 - 22 Mar 2000
Cited by 2 | Viewed by 5867
Abstract
the utilization of substitued dienes with electron-donor groups and under high pressure conditions, induces the dienophilic character of 1-nitronaphtalene in Diels-Alder reactions, giving the products with and without the nitro-group, the yield depending on the nature of the dienes substituent groups. Full article
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Scheme 1

19 KiB  
Abstract
Cyclodextrin Effect on Intramolecular Catalysis
by A. M. Granados, G. O. Andres and R. Hoyos De Rossi
Molecules 2000, 5(3), 405-406; https://doi.org/10.3390/50300405 - 22 Mar 2000
Viewed by 5291
Abstract
HPCD inhibits the hydrolysis reaction of monoamides and monoesters of phthalic and maleic acid at pH 2. The magnitude of inhibition depends on the leaving group. For some of the substrates, the reaction in the cavity is more than 100 times slower than [...] Read more.
HPCD inhibits the hydrolysis reaction of monoamides and monoesters of phthalic and maleic acid at pH 2. The magnitude of inhibition depends on the leaving group. For some of the substrates, the reaction in the cavity is more than 100 times slower than that in solution. Full article
14 KiB  
Abstract
Kinetic Study of the Hydrolisys of Phenyl Perfluorooctanoate in Water: Deaggregation Effect of b-Cyclodextrin
by M. A. Fernández and R. H. De Rossi
Molecules 2000, 5(3), 407-408; https://doi.org/10.3390/50300407 - 22 Mar 2000
Viewed by 7132
Abstract
The kinetics of the hydrolysis of phenyl perfluorooctanoate was studied at pH 6.00 and 9.90 in water. The substrate is aggregated under all working reaction conditions, which is indicated from the decrease in the reaction rate when the substrate concentration is raised. The [...] Read more.
The kinetics of the hydrolysis of phenyl perfluorooctanoate was studied at pH 6.00 and 9.90 in water. The substrate is aggregated under all working reaction conditions, which is indicated from the decrease in the reaction rate when the substrate concentration is raised. The addition of β-cyclodextrin produces the deaggregation of the ester catalyzing the reaction. Full article
16 KiB  
Abstract
Conformational Study of New AZT Derivatives
by M. T. Baumgartner, M. I. Motura, A. B. Pierini and M. C. Briñón
Molecules 2000, 5(3), 409-410; https://doi.org/10.3390/50300409 - 22 Mar 2000
Cited by 2 | Viewed by 6343
Abstract
A conformational study of three new AZT derivatives was made by semiempirical methods in order to find a structural correlation between these derivatives and AZT. Full article
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Figure 1

18 KiB  
Abstract
Computational Study of the Stereoselectivity of Diels-Alder Reactions of D-Glucose-Derived Dienophiles with Cyclopentadiene
by S. C. Pellegrinet, M. T. Baumgartner, A. B. Pierini and R. A. Spanevello
Molecules 2000, 5(3), 411-412; https://doi.org/10.3390/50300411 - 22 Mar 2000
Cited by 1 | Viewed by 6416
Abstract
A computational study was performed in order to rationalize the high exo stereoselectivity in the cycloaddition reactions of sugar-derived dienophiles with cyclopentadiene. Full article
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Figure 1

12 KiB  
Abstract
Comparative Study of Hydrocarbon, Fluorocarbon and Aromatic Bonded RP-HPLC Stationary Phases by Linear Solvation Energy Relationships
by M. Reta, P. W. Carr, P. C. Sadek and S. C. Rutan
Molecules 2000, 5(3), 413; https://doi.org/10.3390/50300413 - 22 Mar 2000
Cited by 1 | Viewed by 5396
Abstract
n/a Full article
15 KiB  
Abstract
Cyclodimerization of Stilbenes and Styrenes Catalyzed by Heteropolyacid Supported on Silica
by E. N. Alesso, J. Aguirre, B. Lantaño, L. Finkielsztein, G. Y. Moltrasio, P. G. Vázquez, L. R. Pizzio, C. Caceres, M. White and H. J. Thomas
Molecules 2000, 5(3), 414-415; https://doi.org/10.3390/50300414 - 22 Mar 2000
Cited by 2 | Viewed by 8176
Abstract
Several stilbenes and styrenes have been treated with heteropolyacid] (HPA) supported over silice. The compounds obtained were characterized by 1H and 13C- NMR and the yields were compared with those obtained using H2SO4 (c) and ethyl poliphosphate] (PPE). Full article
16 KiB  
Abstract
Synthesis of Indanes Via a [3+2] Cycloaddition
by B. Lantaño, L. M. Finkielsztein, E. N. Alesso, J. M. Aguirre and G. Y. Moltrasio
Molecules 2000, 5(3), 416-417; https://doi.org/10.3390/50300416 - 22 Mar 2000
Cited by 1 | Viewed by 5180
Abstract
The acid -promoted [3+2] cycloaddition of alkenes with benzhydrylic alcohols afford products in good yield and with remarkable stereoselectivity. Full article
16 KiB  
Abstract
Synthesis of Heterocylic Compounds of Biological Interest from Carbohydrate Derivatives
by M. F. Martinez Esperón, M. L. Fascio and N. B. D’Accorso
Molecules 2000, 5(3), 418-419; https://doi.org/10.3390/50300418 - 22 Mar 2000
Cited by 2 | Viewed by 5870
Abstract
The synthesis of some isoxazolic compounds from carbohydrate derivatives is described. These products are obtained by 1,3-dipolar cycloaddition reaction and their functionalization leads to derivatives with potential biological activities. Full article
13 KiB  
Abstract
Nuclear Magnetic Resonance for the Structural Study of Bioactive Semicarbazones
by H. Cerecetto, R. Di Maio, M. González, G. Seoane, G. Sagrera and M. Millán
Molecules 2000, 5(3), 420-421; https://doi.org/10.3390/50300420 - 22 Mar 2000
Viewed by 8605
Abstract
NMR studies of bioactive semicarbazones are described. Full article
17 KiB  
Abstract
Antifeedant Activity Evaluation of Withanolides from Jaborosa integrifolia
by Clarisa E. Vaccarini and Gloria M. Bonetto
Molecules 2000, 5(3), 422-423; https://doi.org/10.3390/50300422 - 22 Mar 2000
Cited by 9 | Viewed by 6287
Abstract
Antifeedant activity of the 4-deoxi-27-hydroxi-withanolides (1, 2 y 3) isolated from Jaborosa integrifolia (Solanaceae) was investigated in caterpillar Spodoptera littoralis on Leaf Disk Choice Bioassay. Results indicate that the best feed inhibition effect is due to Jaborosalactone A. Full article
17 KiB  
Abstract
UV Spectral Properties of Benzophenone. Influence of Solvents and Substituents
by G. T. Castro, S. E. Blanco and O. S. Giordano
Molecules 2000, 5(3), 424-425; https://doi.org/10.3390/50300424 - 22 Mar 2000
Cited by 13 | Viewed by 8096
Abstract
The effect of the solvent and the substituents on the UV spectroscopic properties of substituted benzophenones was studied. Full article
16 KiB  
Abstract
Determination of the pKa of Benzophenones in Ethanol-Water
by G. T. Castro, S. E. Blanco and O. S. Giordano
Molecules 2000, 5(3), 426-427; https://doi.org/10.3390/50300426 - 22 Mar 2000
Cited by 9 | Viewed by 7168
Abstract
The pKa of monohydroxylated benzophenones was determined by UV spectroscopy. The values obtained are coherent with the resonant forms and hydrogen bond intramolecular of the analyzed compounds. Full article
24 KiB  
Abstract
Synthesis and In Vitro Antigungal Properties of 4-Aryl-4-Narylamine-1-butenes and Related Compounds
by V. Kouznetsov, J. Urbina, A. Palma, S. López, C. Devia, R. Enriz and S. Zacchino
Molecules 2000, 5(3), 428-430; https://doi.org/10.3390/50300428 - 22 Mar 2000
Cited by 8 | Viewed by 7067
Abstract
A new series of 4-aryl and 4-alkyl-4-N-arylamine-1-butenes (homoallylamines) were synthesized and some of them transformed to 4-aryl or alkylquinolines. All of them showed strong antifungal activities against human pathogenic fungi in vitro, being Epidermophyton floccosum the most susceptible species. Full article
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Scheme 1

19 KiB  
Abstract
SRN1 and Stille Reactions: A New Synthetic Strategy
by Eduardo F. Corsico and Roberto A. Rossi
Molecules 2000, 5(3), 431-432; https://doi.org/10.3390/50300431 - 22 Mar 2000
Cited by 1 | Viewed by 6436
Abstract
The photostimulated reaction of Me3Sn- ion with mono, di and trichloro arenes in liquid ammonia gave very good yields of stannanes by the SRN1 mechanism. These products reacted by a palladium-catalized cross coupling reaction with halobenzenes to give [...] Read more.
The photostimulated reaction of Me3Sn- ion with mono, di and trichloro arenes in liquid ammonia gave very good yields of stannanes by the SRN1 mechanism. These products reacted by a palladium-catalized cross coupling reaction with halobenzenes to give phenylated products also in very goods yields. Similar yields can be obtained in one-pot reactions. Full article
15 KiB  
Abstract
Citotoxic Activity of Extracts and Sesquiterpene Lactones from Stachycephalum argentinum
by R. Alarcón, C. Vaccarini and V. Sosa
Molecules 2000, 5(3), 433-434; https://doi.org/10.3390/50300433 - 22 Mar 2000
Viewed by 5178
Abstract
The extracts and sesquiterpene lactones of S.argentinum were assayed to determine their biological activity on Artemia salina. The most active compound was costunolide (1) with LD50= 62 ppm. Full article
14 KiB  
Abstract
Phytotoxic Activity of a Benzofuran Isolated from Trichocline reptans
by C. Vaccarini, R. Alarcón and V. Sosa
Molecules 2000, 5(3), 435-436; https://doi.org/10.3390/50300435 - 22 Mar 2000
Cited by 2 | Viewed by 5258
Abstract
Phytotoxic Activity of the 6-acetyl-5-hydroxy-2isopropenyl-2,3-dihydrobenzofurane (1) isolated from Trichocline reptans (Asteraceae) was investigated in two weed species. Results indicate that the best growth inhibition effect ocurres on Chenopodium album weed. Phythotoxic effect of the T. reptans chloroformic extract and of the [...] Read more.
Phytotoxic Activity of the 6-acetyl-5-hydroxy-2isopropenyl-2,3-dihydrobenzofurane (1) isolated from Trichocline reptans (Asteraceae) was investigated in two weed species. Results indicate that the best growth inhibition effect ocurres on Chenopodium album weed. Phythotoxic effect of the T. reptans chloroformic extract and of the benzofurane are discussed and compared in the two weed species. Full article
18 KiB  
Abstract
Fluorimetric Determination of Carbamate Pesticides in Host-Guest Complexes
by Alicia Viviana Veglia
Molecules 2000, 5(3), 437-438; https://doi.org/10.3390/50300437 - 22 Mar 2000
Cited by 9 | Viewed by 4943
Abstract
From the effect of β-cyclodextrin and hydroxypropyl-β-cyclodextrin on the UVvisible and fluorescence spectra of carbaryl and carbofuran, the values of association constants were determined. The ratio of the fluorescence quantum yields for the bound and free substrates indicated an enhanced fluorimetric method of [...] Read more.
From the effect of β-cyclodextrin and hydroxypropyl-β-cyclodextrin on the UVvisible and fluorescence spectra of carbaryl and carbofuran, the values of association constants were determined. The ratio of the fluorescence quantum yields for the bound and free substrates indicated an enhanced fluorimetric method of detection. Full article
16 KiB  
Abstract
Synthesis of Ethylenic and Acetylenic Triorganotins with Bulky Organic Ligands
by V. Dodero, L. C. Koll and J. C. Podestá
Molecules 2000, 5(3), 439-440; https://doi.org/10.3390/50300439 - 22 Mar 2000
Viewed by 5611
Abstract
The syntheses of trineophyl- (1a) and tri-(-)-menthylstannyl phenylacetylene (1b) as well as that of (E)-1-trineophylestannyl-2-phenylethene (2) and (E)-1-trineophylstannyl-1,2-diphenylethene (3) are described. The hydrostannation of 1a with an excess of trimethyltin hydride led to 1,1,1-tris(trimethyltin)-2-phenylethane (4) and/or 1,1-bis(trimethyltin)-2-phenylethene (5) depending on the reaction conditions. [...] Read more.
The syntheses of trineophyl- (1a) and tri-(-)-menthylstannyl phenylacetylene (1b) as well as that of (E)-1-trineophylestannyl-2-phenylethene (2) and (E)-1-trineophylstannyl-1,2-diphenylethene (3) are described. The hydrostannation of 1a with an excess of trimethyltin hydride led to 1,1,1-tris(trimethyltin)-2-phenylethane (4) and/or 1,1-bis(trimethyltin)-2-phenylethene (5) depending on the reaction conditions. Full article
18 KiB  
Abstract
New Spiranoid Withanolides From Jaborosa Odonelliana
by A. M. Cirigliano, A. S. Veleiro, J. C. Oberti and G. Burton
Molecules 2000, 5(3), 441-442; https://doi.org/10.3390/50300441 - 22 Mar 2000
Cited by 1 | Viewed by 5113
Abstract
From whole Jaborosa odonelliana plants four new withanolides containing a spiranic lactone in the side chain, were isolated and their structures elucidated by spectroscopic methods. Full article
17 KiB  
Abstract
Synthesis of Aziridinosteroids
by P. Di Chenna, P. Dauban, A. A. Ghini, G. Burton and R. H. Dodd
Molecules 2000, 5(3), 443-444; https://doi.org/10.3390/50300443 - 22 Mar 2000
Cited by 1 | Viewed by 5764
Abstract
11α,12α-aziridinosteroids (2a, b, c) were prepared from 5β-H-11-pregnene-3,20-dione (1) using different iminophenyliodinanes and cloramine aziridination reagents. Full article
15 KiB  
Abstract
3,3-Dimethylacylthioureas: "S", "-S", "U" or "W" Conformation?
by M. Sosa, M. Piris and G. Burton
Molecules 2000, 5(3), 445-446; https://doi.org/10.3390/50300445 - 22 Mar 2000
Viewed by 7805
Abstract
We report a study of 3,3-dimethyl substituted acylthioureas. X ray data and quantum mechanical calculations demonstrated that the "S" conformation is the most stable both for the acylthioureas and the corresponding anions. The high regioselectivity towards S-alkylation is explained on the basis of [...] Read more.
We report a study of 3,3-dimethyl substituted acylthioureas. X ray data and quantum mechanical calculations demonstrated that the "S" conformation is the most stable both for the acylthioureas and the corresponding anions. The high regioselectivity towards S-alkylation is explained on the basis of the localization of the HOMO mainly over the sulfur atom. Full article
20 KiB  
Abstract
Synthesis of D-Homo Analogs of Neurosteroids
by P. Di Chenna, A. A. Ghini and G. Burton
Molecules 2000, 5(3), 447-448; https://doi.org/10.3390/50300447 - 22 Mar 2000
Cited by 2 | Viewed by 5665
Abstract
17(13→18)-Abeo and D-homo analogs of the natural neurosteroid 3α-hydroxy-5αH-pregnan-20-one were prepared by anionic or radical (mercury (II) hydride mediated) rearrangements of steroidal cyclopropylketones respectively. Full article
18 KiB  
Abstract
A New Rearranged Non-Aromatic Salpichrolide from Salpichroa Origanifolia
by M. C. Tettamanzi, A. S. Veleiro, J. R. De La Fuente and G. Burton
Molecules 2000, 5(3), 449-450; https://doi.org/10.3390/50300449 - 22 Mar 2000
Viewed by 6615
Abstract
From the aerial parts of Salpichroa origanifolia a new withanolide in which the C-13 angular methyl has migrated to C-17, was isolated and characterized by spectroscopic methods. Full article
16 KiB  
Abstract
Reactivity Comparison of D–Glucose–Derived Dienophiles. Analysis of the Conformational and Electronic Properties
by S. C. Pellegrinet, M. T. Baumgartner and R. A. Spanevello
Molecules 2000, 5(3), 451-452; https://doi.org/10.3390/50300451 - 22 Mar 2000
Cited by 1 | Viewed by 5873
Abstract
Semiempirical calculations were performed to carry out a conformational analysis for carbohydrate-derived dienophiles 1-4. For α,β-unsaturated carbonylic compounds 2-4, a good correlation between Diels-Alder reactivity with calculated values for LUMO energies was observed. Full article
18 KiB  
Abstract
Teorethical Studies of the Stability of 8a-Alkyll-1,2,3,4,6,8ahexahydronaphtalen-1-ones Using Semiempirical Methods
by Guillermo R. Labadie, Raquel M. Cravero, Guillermina Estiú and Manuel Gonzalez Sierra
Molecules 2000, 5(3), 453-454; https://doi.org/10.3390/50300453 - 22 Mar 2000
Cited by 1 | Viewed by 8101
Abstract
The Birch alkylation products are very unstable. We are showing, in this communication, the results of a theoretical study that compares different decomposition reaction mechanisms. The conclusions are in agreement with our experimental results. Full article
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Figure 1

21 KiB  
Abstract
Photochemical Study of the Reactions of the 2-Naphtoxide Ion with Haloadamantanes
by Juan E. Argüello, Marcelo Puiatti and Alicia B. Peñéñory
Molecules 2000, 5(3), 455-456; https://doi.org/10.3390/50300455 - 22 Mar 2000
Cited by 1 | Viewed by 7111
Abstract
The fluorescent excited state of 2-naphtoxide ion is quenched by haloadamantanes (X-Ada) as electron acceptors according to an electron-transfer mechanism. This mechanism is proposed on the basis of:1) decreasing quenching rate constant as the reduction potential of X-Ada is made more negative and [...] Read more.
The fluorescent excited state of 2-naphtoxide ion is quenched by haloadamantanes (X-Ada) as electron acceptors according to an electron-transfer mechanism. This mechanism is proposed on the basis of:1) decreasing quenching rate constant as the reduction potential of X-Ada is made more negative and 2) the analysis of reaction products. Full article
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Figure 1

19 KiB  
Abstract
A Different Behaviour of the Phthalimide Ion in Srn1 Reactions
by Manuel Bajo Maquieira, Alicia B. Peñéñory and Roberto A. Rossi
Molecules 2000, 5(3), 457-458; https://doi.org/10.3390/50300457 - 22 Mar 2000
Cited by 1 | Viewed by 5117
Abstract
The phthalimide anion reacts by the SRN1 mechanism under photostimulation with different substrates. Whilst with 1-iodonaphthalene only reduction of the naphthyl radical is observed, with 1-iodoadamantane coupling at the carbon instead of at the nitrogen takes place. Full article
20 KiB  
Abstract
Variation in the Composition of the Essential Oil of Senecio Filaginoides Dc
by V. T. Balzaretti, A. Arancibia, A. Marchiaro, M. E. Arce and M. S. Feijóo
Molecules 2000, 5(3), 459-461; https://doi.org/10.3390/50300459 - 22 Mar 2000
Cited by 13 | Viewed by 4644
Abstract
n/a Full article
19 KiB  
Abstract
Gastric Cytoprotective Activity of Ilicic Aldehyde in Rats and Mice
by O. J. Donadel, A. María, G. Wendel, E. Guerreiro and O. Giordano
Molecules 2000, 5(3), 462-464; https://doi.org/10.3390/50300462 - 22 Mar 2000
Viewed by 5667
Abstract
Ilicic alcohol, a natural sesquiterpene, was converted into an aldehyde by using Jones’ oxidation. The gastroprotective activity of ilicic aldehyde was evaluated in mice and rats. Full article
19 KiB  
Abstract
Chemical Components and Biological Activity of Bidens Subalternans, B. Aurea (Astereaceae) and Zuccagnia Puntacta (Fabaceae)
by C. A. Ortega, A. O.M. María and J. C. Gianello
Molecules 2000, 5(3), 465-467; https://doi.org/10.3390/50300465 - 22 Mar 2000
Cited by 10 | Viewed by 6292
Abstract
The aim of this work was to evaluate the activity in the gastrointestinal tract of the several extracts and pure components isolated from Bidens species and Zuccagnia puntacta. Full article
16 KiB  
Abstract
Regioselective Opening of Epoxides Catalyzed by Sn (IV). A New Method for the Synthesis of Halohydrins?
by Claudio J. Salomon
Molecules 2000, 5(3), 468-469; https://doi.org/10.3390/50300468 - 22 Mar 2000
Viewed by 4750
Abstract
The regioselective opening of epoxides with organotin oxides 1 and 2, in presence of halogenated alcohols was developed, yielding the halohydrin derivatives. Full article
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Scheme 1

15 KiB  
Abstract
Phytochemical Study of Condalia microphylla Cav.
by M. A. Frontera, M. A. Tomás, A. Diez, C. Watson and C. Mulet
Molecules 2000, 5(3), 470-471; https://doi.org/10.3390/50300470 - 22 Mar 2000
Cited by 4 | Viewed by 7130
Abstract
From the petroleum ether extract of the aereal part of Condalia microphylla Cav, hydrocarbons, sterols, alcohols, and fatty acids were isolated. From fruits of the same plant anthocyanins were also isolated and characterized by chromatographic and spectroscopic methods. Full article
18 KiB  
Abstract
Isomerisation of Methyl (E) 2-Bromo-3-(4-XC6H4)-propenoates
by Mercedes A. Badajoz, Rosana S. Montani and Mercedes Cabaleiro
Molecules 2000, 5(3), 472-474; https://doi.org/10.3390/50300472 - 22 Mar 2000
Viewed by 4737
Abstract
The geometric isomerisation of the title compound induced by bromine or chlorine appears to involve ionic pair species resulting from the nucleophilic attack of the halogen. Full article
21 KiB  
Abstract
Lipoxygenase-1 Activity of Soybean Genotypes Grown in Argentina
by J. M. Meriles, C. A. Guzmán and D. M. Maestri
Molecules 2000, 5(3), 475-478; https://doi.org/10.3390/50300475 - 22 Mar 2000
Cited by 6 | Viewed by 4770
Abstract
The lipoxygenase-1 (LOX-1) activity of 19 soybean genotypes was quantified in two consecutive years. The LOX-1 activity produced by any cultivar was essentially the same in both, 1995 and 1996 crop years. The lowest values of LOX-1 activity were found in NK 555 [...] Read more.
The lipoxygenase-1 (LOX-1) activity of 19 soybean genotypes was quantified in two consecutive years. The LOX-1 activity produced by any cultivar was essentially the same in both, 1995 and 1996 crop years. The lowest values of LOX-1 activity were found in NK 555 cultivar whereas Asgrow 5409 cultivar had the highest values. Full article
18 KiB  
Abstract
1H and 13C-NMR Spectroscopic Study of Some 1H-4,5-Dihydroimidazolium Salts
by Alejandra Salerno and Isabel A. Perillo
Molecules 2000, 5(3), 479-480; https://doi.org/10.3390/50300479 - 22 Mar 2000
Viewed by 5724
Abstract
The 1H y 13C-NMR spectra of some 1,3 and 1,2,3-trisubstituted 1H-4,5-dihydroimidazolium salts are analyzed. Full article
17 KiB  
Abstract
Improved Synthesis of N-Substituted Quinolinimides Using Microwave Irradiation
by M. M. Blanco, I. A. Perillo and C. B. Schapira
Molecules 2000, 5(3), 481-482; https://doi.org/10.3390/50300481 - 22 Mar 2000
Cited by 2 | Viewed by 5130
Abstract
The synthesis of several quinolinimidoacetic acid derivatives (I) by two different routes, starting from quinolinic anhydride or quinolinimide, is described. In all cases better yields and decreased reaction times were achieved employing microwave irradiation as an alternative source of energy. Full article
15 KiB  
Abstract
Conformational Analysis of Seven Membered Nitrogen Heterocycles Employing Molecular Modeling. Part II: 1-(ONitrophenyl)-2-Phenyl-1h-4,5,6,7-Tetrahydro-1,3-Diazepine
by Mónica E. Hedrera, Adriana Robinsohn and Isabel A. Perillo
Molecules 2000, 5(3), 483-484; https://doi.org/10.3390/50300483 - 22 Mar 2000
Cited by 2 | Viewed by 5166
Abstract
Geometry optimization of 1-(o-nitrophenyl)-2-phenyl-1H-4,5,6,7-tetrahydro-1,3-diazepine is performed by means of molecular modeling. Results are correlated with theoretical and experimental UV spectra. Full article
15 KiB  
Abstract
New Peanut Product: “Mayonnaise”. Some Chemical Aspects
by M. G. Johnston, V. M. Navarro, V. Nepote, N. R. Grosso, N. I. Brutti and C. A. Guzmán
Molecules 2000, 5(3), 485-486; https://doi.org/10.3390/50300485 - 22 Mar 2000
Viewed by 5359
Abstract
The percentage composition, fatty acids and oxidation stability was obtained from “peanut mayonnaise” in comparison with commercial mayonnaise and sunflower oil. “Peanut mayonnaise” showed better chemical quality than commercial mayonnaise. Full article
16 KiB  
Abstract
Antioxidant Activity of Methanolic Extracts from Peanut Skin
by V. Nepote, N. R. Grosso and C. A. Guzmán
Molecules 2000, 5(3), 487-488; https://doi.org/10.3390/50300487 - 22 Mar 2000
Cited by 9 | Viewed by 6739
Abstract
Antioxidant activity of skin from runner peanut was performed on sunflower refined oil. The skin was obtained from industrial blanching process. The oil was oxidized at 60ºC. The methanolic extracts show antioxidant activity in relation to the oil (without additives). However these extracts [...] Read more.
Antioxidant activity of skin from runner peanut was performed on sunflower refined oil. The skin was obtained from industrial blanching process. The oil was oxidized at 60ºC. The methanolic extracts show antioxidant activity in relation to the oil (without additives). However these extracts do not reach the activity level from BHT. Full article
17 KiB  
Abstract
Relationship Between the Conformation of the Cyclopeptides Isolated from the Fungus Amanita Phalloides (Vaill. Ex Fr.) Secr. and Its Toxicity
by M. E. Battista, A. A. Vitale and A. B. Pomilio
Molecules 2000, 5(3), 489-490; https://doi.org/10.3390/50300489 - 22 Mar 2000
Cited by 5 | Viewed by 5152
Abstract
The electronic structures and conformational studies of the cyclopeptides, Omethyl-α-amanitin, phalloidin and antamanide, were obtained from molecular parameters on the basis of semiempiric and ab initio methods. Full article
20 KiB  
Abstract
Synthetic Studies on Natural Stephaoxocanes. Elaboration of a Tetrahydrooxazaphenalene Potential Intermediate
by Teodoro Saul Kaufman
Molecules 2000, 5(3), 491-492; https://doi.org/10.3390/50300491 - 22 Mar 2000
Cited by 2 | Viewed by 5155
Abstract
The elaboration of a 2,3,7-9a-tetrahydro-1H-8-oxa-1-aza-phenalen-9-one derivative, as a potential key intermediate for the synthesis of stephaoxocanes, employing Jackson’s tosylamidoacetal cyclization, is presented. Full article
21 KiB  
Abstract
Elaboration of the Isochromane System of Stephaoxocanes Employing an Oxa-Pictet Spengler Type Cyclization
by Teodoro S. Kaufman, Carmem R. Bernardi, Marcos Cipulli and Claudio C. Silveira
Molecules 2000, 5(3), 493-494; https://doi.org/10.3390/50300493 - 22 Mar 2000
Cited by 5 | Viewed by 6796
Abstract
An approach to the synthesis of the isochromane moiety embodying the AC-ring system of the stephaoxocanes, by the use of an Oxa-Pictet Spengler type cyclization strategy, is reported. Full article
16 KiB  
Abstract
Practical and Efficient Procedure for the In Situ Preparation of B-Alkoxyoxazaborolidines. Enantioselective Reduction of Prochiral Ketones
by Viviana L. Ponzo and Teodoro S. Kaufman
Molecules 2000, 5(3), 495-496; https://doi.org/10.3390/50300495 - 22 Mar 2000
Cited by 2 | Viewed by 5987
Abstract
A new method for the in situ elaboration of B-alkoxyoxazaborolidines is presented. Their use in the enantioselective reduction of prochiral aromatic ketones provides excellent chemical and optical yields of chiral alcohols. Full article
14 KiB  
Abstract
Synthetic Modifications of Lead Compounds as Antitrypanosomal Drugs
by H. Cerecetto, R. Di Maio, G. Seoane, A. Denicola, G. Peluffo and C. Quijano
Molecules 2000, 5(3), 497-498; https://doi.org/10.3390/50300497 - 22 Mar 2000
Viewed by 6521
Abstract
Following our work in the synthesis of compounds with antichagasic activity, we describe new potential products in which the same "leader" compound was modulated. Full article
16 KiB  
Abstract
Synthesis of 1,2,6-Thiadiazin 1,1-Dioxide Derivatives as Trypanocidal Agents
by H. Cerecetto, R. Di Maio, G. Seoane, C. Ochoa, A. Gómez-Barrio and S. Muelas
Molecules 2000, 5(3), 499-500; https://doi.org/10.3390/50300499 - 22 Mar 2000
Viewed by 6965
Abstract
It describes the synthesis of new 1,2,6-Thiadiazin 1,1-dioxide derivatives using condensation of the Knoevenagel type. The products are evaluated in vitro as trypanocidal agents. Full article
16 KiB  
Abstract
Reactivity Studies of 5,6-Dimethyl- and 3,5,6-Trimethyl -1,2,4-Triazine–N4-Oxide Against Different Electrophiles
by H. Cerecetto, M. González, P. Saenz and G. Seoane
Molecules 2000, 5(3), 501-502; https://doi.org/10.3390/50300501 - 22 Mar 2000
Viewed by 5923
Abstract
It describes the regioselectivity studies of 5,6-Dimethyl-1,2,4-triazine-N4-oxide using different electrophiles. Full article
15 KiB  
Abstract
Addition of Aromatic Nucleophiles to a C=N Double Bond of 1,2,5-Thiadiazole 1,1-Dioxide
by M. F. Rozas, O. E. Piro, E. E. Castellano, M. V. Mirífico and E. J. Vasini
Molecules 2000, 5(3), 503-504; https://doi.org/10.3390/50300503 - 22 Mar 2000
Cited by 7 | Viewed by 7026
Abstract
A new synthesis of 3,4-diphenyl-4-aryl-1,2,5-thiadiazolines 1,1-dioxide through the addition of aromatic derivatives to 1,2,5-thiadiazole 1,1-dioxide is presented. Anhydrous AlCl3 is used as catalyst. Full article
24 KiB  
Abstract
Studies on a New Synthetic Route towards Cassiol
by M. I. Colombo, J. A. Bacigaluppo, J. Zinczuk, M. P. Mischne and E. A. Rúveda
Molecules 2000, 5(3), 505-507; https://doi.org/10.3390/50300505 - 22 Mar 2000
Cited by 1 | Viewed by 5521
Abstract
The synthesis of the acyclic intermediate 7 towards the preparation of cassiol (2) is described. The cyclization of 7 led to 5, a precursor of 2 and to the unexpected product 8. Full article
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Scheme 1

15 KiB  
Abstract
Synthesis and Characterization of New Naphthoquinonic Derivatives Containing the Pyrazole Ring: Pyrazolylnaphthoquinones
by Norma R. Sperandeo and María M. De Bertorello
Molecules 2000, 5(3), 508-509; https://doi.org/10.3390/50300508 - 22 Mar 2000
Cited by 2 | Viewed by 5252
Abstract
The reaction of 3-aminopyrazole (1) with 1,2-naphthoquinone-4-sulfonic acid sodium salt (2) was studied in different aqueous media. The novel pyrazolylnaphthoquinones synthesized were physical and spectroscopically characterized, including 2D NMR spectroscopy (HETCOR). The possible reaction mechanism is proposed. Full article
15 KiB  
Abstract
Determination of the Formation Constant of the Inclusion Complex from a Naphthoquinone
by Gladys Granero, Marcela Longhi and María M. De Bertorello
Molecules 2000, 5(3), 510-511; https://doi.org/10.3390/50300510 - 22 Mar 2000
Cited by 1 | Viewed by 5407
Abstract
Inclusion complexation of 1 with HP-β-CD or HP-β-CD:PVP K30 in aqueous solution was spectroscopically studied and the formation constant for a 1:1 complex was determined from these measurements. Full article
15 KiB  
Abstract
Binding Constant of Amines to Water/AOT/n-Hexene Reverse Micelles. Influence of the Chemical Structure
by L. Zingaretti, N. M. Correa, L. Boscatto, S. M. Chiachiera, E. N. Durantini, S. G. Bertolotti, C. V. Rivarola and J. J. Silber
Molecules 2000, 5(3), 512-513; https://doi.org/10.3390/50300512 - 22 Mar 2000
Cited by 1 | Viewed by 5890
Abstract
The distribution of different amines between n-hexane bulk and the micellar pseudophase of AOT reverse micelles were measured by a fluorometric method. An independent method was used to corroborate the incorporation of the amines to the interface. The effect of the amine structure [...] Read more.
The distribution of different amines between n-hexane bulk and the micellar pseudophase of AOT reverse micelles were measured by a fluorometric method. An independent method was used to corroborate the incorporation of the amines to the interface. The effect of the amine structure on the binding constant was analysed. Full article
17 KiB  
Abstract
New Withanolides from Two Varieties of Jaborosa Caulescens
by Viviana E. Nicotra, Roberto R. Gil, Juan C. Oberti and Gerardo Burton
Molecules 2000, 5(3), 514-515; https://doi.org/10.3390/50300514 - 22 Mar 2000
Cited by 3 | Viewed by 6947
Abstract
The phytochemical study of two species of Jaborosa caulescens (var. caulescens and var. bipinnatifida) yielded the four new withanolides 1-4. The structures of the new compounds were determined using a combination of spectroscopic techniques (including 1D and 2D NMR) and Molecular Modeling. Full article
14 KiB  
Abstract
Formation of Complexes of Flavonoids and Metals. Determination of the Stoichiometry and Stability Constants
by M. G. Barolli, R. Alonso Werner, L. D. Slep and A. B. Pomilio
Molecules 2000, 5(3), 516-517; https://doi.org/10.3390/50300516 - 22 Mar 2000
Cited by 7 | Viewed by 6319
Abstract
The complexes between some flavonoids and metals (Co(II), Cu(II), Mn(II), Mg(II), Sn(II)) have been studied by spectrophotometric methods in order to determine the stoichiometry and stability constants. Full article
16 KiB  
Abstract
Analysis by Mass Spectrometry of the Polar Lipids from the Cellular Membrane of Thermophilic Lactic Acid Bacteria
by M. L. Fernández Murga, G. Cabrera, G. Martos, G. Font de Valdez and A. M. Seldes
Molecules 2000, 5(3), 518-519; https://doi.org/10.3390/50300518 - 22 Mar 2000
Cited by 2 | Viewed by 5903
Abstract
Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids from the cellular membrane of Lactobacillus delbruekii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. Analysis of spectra provided useful information about the molecular species and aminoacids constituents of [...] Read more.
Fast atom bombardment (FAB) technique was employed to determine the structure of polar lipids from the cellular membrane of Lactobacillus delbruekii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. Analysis of spectra provided useful information about the molecular species and aminoacids constituents of the samples. Full article
17 KiB  
Abstract
Chemical Modifications of 1,2,5-Oxadiazole N-Oxide System Searching for Cytotoxic Selective Hypoxic Drugs
by M. Boiani, H. Cerecetto, M. González, M. Risso, G. Seoane, G. Sagrera, O. Ezpeleta, A. López de Ceráin and A. Monge
Molecules 2000, 5(3), 520-521; https://doi.org/10.3390/50300520 - 22 Mar 2000
Cited by 1 | Viewed by 7192
Abstract
New analogues of 3-Formyl-4-phenyl-1,2,5-oxadiazole N-oxide (1) are prepared and evaluated as cytotoxic selective agents in hypoxia. Full article
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Figure 1

17 KiB  
Abstract
Approach to the A-B Ring System of Forskolin through Biotransformation of Toluene
by V. Schapiro, G. Seoane and G. García
Molecules 2000, 5(3), 522-523; https://doi.org/10.3390/50300522 - 22 Mar 2000
Viewed by 6095
Abstract
In the present work, we will intend to show that diol I, microbially derived from toluene using Pseudomonas putida 39D, is a suitable synthon for the synthesis of the A-B ring system of forskolin. The functionalization of diol I, to be used as [...] Read more.
In the present work, we will intend to show that diol I, microbially derived from toluene using Pseudomonas putida 39D, is a suitable synthon for the synthesis of the A-B ring system of forskolin. The functionalization of diol I, to be used as ring-B, and the attempts of ring-A closure, will be disclosed. Full article
17 KiB  
Abstract
Shelf-Life of an Extruded Blend of Peanut, Soybean and Corn
by V. S. Bustamante and C. A. Guzmán
Molecules 2000, 5(3), 524-525; https://doi.org/10.3390/50300524 - 22 Mar 2000
Viewed by 4913
Abstract
The Shelf-Life (SL) of peanut, soybean and corn blend extruded without (A) and with butylhydroxytoluol (B) and extract of Rosmarinum sp (C) was determined. Only B significativaly increased SL. In function of temperature would be defined by: A- SL = e -0.0465x + [...] Read more.
The Shelf-Life (SL) of peanut, soybean and corn blend extruded without (A) and with butylhydroxytoluol (B) and extract of Rosmarinum sp (C) was determined. Only B significativaly increased SL. In function of temperature would be defined by: A- SL = e -0.0465x + 5.1762, B- SL = e -0.0421x + 5.3332, C- SL = e -0.581x +5.626 Full article
22 KiB  
Abstract
A Facile High-Yield Synthesis of [10 B]-8-Dihydroxyboryl Harmine, a Potential Agent for Boron Neutron Capture Therapy
by Jose A. Sintas, Norberto J. Macareno and Arturo A. Vitale
Molecules 2000, 5(3), 526-528; https://doi.org/10.3390/50300526 - 22 Mar 2000
Viewed by 3937
Abstract
n/a Full article
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Scheme 1

16 KiB  
Abstract
Synthesis of Diads and Triads Derived from Carotenoids and Fullerene C60
by E. N. Durantini, Ana Moore, Thomas A. Moore and Devens Gust
Molecules 2000, 5(3), 529-530; https://doi.org/10.3390/50300529 - 22 Mar 2000
Cited by 4 | Viewed by 6493
Abstract
A convenient procedure for the synthesis of supramolecules bearing carotenoids and fullerene C60 is reported. The amphipathic nature and the high yield of charge separation of these compounds make them candidates in the formation of transmembrane charge gradients. Full article
15 KiB  
Abstract
Synthesis of Asymmetrical Porphyrins Substituted in the meso-Position from Dipyrrolomethanes
by E. Milanesio, S. M. Chiacchiera, J. J. Silber and E. N. Durantini
Molecules 2000, 5(3), 531-532; https://doi.org/10.3390/50300531 - 22 Mar 2000
Viewed by 5590
Abstract
A convenient procedure for the synthesis of 5-(4-acetamidophenyl)-10,15,20-tris(4-substituted phenyl) porphyrins from dipyrrolomethane is reported. meso-(4-Substituted phenyl) dipyrrolomethanes were obtained in yields of 72-84%. The amide porphyrins were isolated with appreciable yields of 15-17%. Full article
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Scheme 1

15 KiB  
Abstract
A Simple Enzymatic Preparation of 2’,3’-Di-OAcetylnucleosides Through a Lipase Catalyzed Alcoholysis
by Alejandra Zinni, Alejandro Schmidt, Mariana Gallo, Luis Iglesias and Adolfo Iribarren
Molecules 2000, 5(3), 533-534; https://doi.org/10.3390/50300533 - 22 Mar 2000
Cited by 3 | Viewed by 5385
Abstract
Several 2’,3’-di-O-acetylnucleosides (2a-d) were obtained regioselectively through a Candida antarctica B lipase catalyzed alcoholysis. Full article
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Scheme 1

17 KiB  
Abstract
Escherichia Coli Bl21: A Useful Biocatalyst for the Synthesis of Purine Nucleosides
by M. C. Rogert, N. Martínez, S. Porro, E. Lewkowicz and A. Iribarren
Molecules 2000, 5(3), 535-536; https://doi.org/10.3390/50300535 - 22 Mar 2000
Viewed by 5782
Abstract
E. coli BL21 cells were able to synthesize several purine nucleosides from pyrimidine ones. Kinetics and yields of this reaction showed a strong dependence on pH, temperature, reagent concentrations and weight of wet cell paste. Yields over 90% were reached in the synthesis [...] Read more.
E. coli BL21 cells were able to synthesize several purine nucleosides from pyrimidine ones. Kinetics and yields of this reaction showed a strong dependence on pH, temperature, reagent concentrations and weight of wet cell paste. Yields over 90% were reached in the synthesis of adenosine. Full article
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Figure 1

31 KiB  
Abstract
Solid-Phase Organic Chemistry: Synthesis of 2β-(Heterocyclylthiomethyl)Penam Derivatives on Solid Support
by Carina M.L. Delpiccolo and Ernesto G. Mata
Molecules 2000, 5(3), 537-538; https://doi.org/10.3390/50300537 - 22 Mar 2000
Cited by 4 | Viewed by 5789
Abstract
The synthesis of 2β-(heterocyclylthiomethyl)penam derivatives on solid support has been developed. Compounds are obtained in good to high yields (based on loading of the original resin). The key step is the solid-phase double rearrangement of the corresponding penicillin sulfoxide. Full article
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Scheme 1

21 KiB  
Abstract
Stereoelectronic Contributions to 1H-1H Coupling Constants
by E. M. Sproviero and G. Burton
Molecules 2000, 5(3), 539-540; https://doi.org/10.3390/50300539 - 22 Mar 2000
Viewed by 5154
Abstract
The effect of stereoelectronic interactions on coupling constants is shown. The analysis is done with a new approach in which a selected interaction is deleted and the effect over the couplings is analyzed. 1H-1H magnetic couplings three and four bonds [...] Read more.
The effect of stereoelectronic interactions on coupling constants is shown. The analysis is done with a new approach in which a selected interaction is deleted and the effect over the couplings is analyzed. 1H-1H magnetic couplings three and four bonds apart in hydrocarbons are shown. Full article
15 KiB  
Abstract
Alkali Treatment of the Polysaccharides from the Cystocarpic Stage from Iridaea Undulosa
by María L. Flores, Alberto S. Cerezo and Carlos A. Stortz
Molecules 2000, 5(3), 541-542; https://doi.org/10.3390/50300541 - 22 Mar 2000
Cited by 2 | Viewed by 5861
Abstract
The polysaccharides from cystocarpic Iridaea undulosa, soluble and insoluble in 2M potassium chloride, Cs and Ci, respectively, were treated with alkali and fractionated by precipitation with increasing concentrations of KCl. They were later separated by ionexchange chromatography, to yield fractions enriched in [...] Read more.
The polysaccharides from cystocarpic Iridaea undulosa, soluble and insoluble in 2M potassium chloride, Cs and Ci, respectively, were treated with alkali and fractionated by precipitation with increasing concentrations of KCl. They were later separated by ionexchange chromatography, to yield fractions enriched in an α-(1→6)-glucan, agaroids and carrageenans. Full article
15 KiB  
Abstract
The 75% Isopropanol-Soluble Polysaccharides from the Endosperm of the Legume Seed of Gleditsia Triacanthos
by Diego A. Navarro, Alberto S. Cerezo and Carlos A. Stortz
Molecules 2000, 5(3), 543-544; https://doi.org/10.3390/50300543 - 22 Mar 2000
Cited by 5 | Viewed by 5436
Abstract
The 75% isopropanol-soluble material from the endosperm of the legume-seed of Gleditsia triacanthos was isolated. The material extracted with boiling water was fractionated by ion-exchange chromatography and characterized. Besides minor amounts of galactomannans, major proportions of arabinans and/or arabinogalactans appear. Full article
15 KiB  
Abstract
Studies of Lipids and Proteins in a Wild Species of the Arachis (Fabaceae) Gender
by A. N. Giannuzzo, N. R. Grosso and C. A. Guzmán
Molecules 2000, 5(3), 545-546; https://doi.org/10.3390/50300545 - 22 Mar 2000
Cited by 2 | Viewed by 4981
Abstract
Chemical components of eight wild species of Arachis were studied. The objectives were to know the chemical composition and establish chemotaxonomic relationships. The results indicate that A. villosa is suitable for breeding program of cultivated peanut. A. monticola and A. batizocoi showed major [...] Read more.
Chemical components of eight wild species of Arachis were studied. The objectives were to know the chemical composition and establish chemotaxonomic relationships. The results indicate that A. villosa is suitable for breeding program of cultivated peanut. A. monticola and A. batizocoi showed major chemical affinity with A. hipogaea. Full article
16 KiB  
Abstract
Antiinflammatory Activity of Cinnamic Acid Esters
by M. E. Godoy, A. Rotelli, L. Pelzer and C. E. Tonn
Molecules 2000, 5(3), 547-548; https://doi.org/10.3390/50300547 - 22 Mar 2000
Cited by 24 | Viewed by 5846
Abstract
The cinnamate esters of 3-p-menthanol (trivial name, menthol) (1) and 4(8)-pmenthen-3-ol (trivial name, pulegol) (2) were prepared and their anti-inflammatory activity was measured. Some of the monoterpenoid esters displayed interesting anti-inflammatory activity. Full article
15 KiB  
Abstract
Use of Cyclic Di- and Triperoxides as Initiators of Styrene Polymerization at High Temperature with a View to Their Use in Industrial Applications
by G. Morales, G. N. Eyler, J. R. Cerna and A. I. Cañizo
Molecules 2000, 5(3), 549-550; https://doi.org/10.3390/50300549 - 22 Mar 2000
Cited by 7 | Viewed by 7313
Abstract
In industry, the bulk free radical polymerization of styrene takes place with the aid of peroxide initiators such as benzoyl peroxide. In this work di- and trimeric cyclic peroxides were used as initiators of the styrene polymerization in order to increase the rate [...] Read more.
In industry, the bulk free radical polymerization of styrene takes place with the aid of peroxide initiators such as benzoyl peroxide. In this work di- and trimeric cyclic peroxides were used as initiators of the styrene polymerization in order to increase the rate of polymerization and molecular weights simultaneously. Full article
15 KiB  
Abstract
Polisaccharides from Cystocarpic Plants of the Red Seaweed Callophyllis Variegata
by E. R. Merino, A. S. Cerezo and M. C. Matulewicz
Molecules 2000, 5(3), 551-552; https://doi.org/10.3390/50300551 - 22 Mar 2000
Cited by 3 | Viewed by 5384
Abstract
The crude polysaccharide from cystocarpic Callophyllis variegata was fractionated with potassium chloride yielding three minor fractions which precipitated between 0.05-0.10 M KCl, 1.20-1.25 M KCl and 1.80-2.00 M KCl, and a main product soluble in 2.00 M KCl. These fractions were analysed and [...] Read more.
The crude polysaccharide from cystocarpic Callophyllis variegata was fractionated with potassium chloride yielding three minor fractions which precipitated between 0.05-0.10 M KCl, 1.20-1.25 M KCl and 1.80-2.00 M KCl, and a main product soluble in 2.00 M KCl. These fractions were analysed and structural analysis of the major one was carried out by methylation, FT-IR and 13C NMR. Full article
16 KiB  
Abstract
Comparison Between Aqueous and Nonaqueous AOT-Heptane Reverse Micelles Using Acridine Orange as Molecular Probe
by R. D. Falcone, N. M. Correa, M. A. Biasutti and J. J. Silber
Molecules 2000, 5(3), 553-554; https://doi.org/10.3390/50300553 - 22 Mar 2000
Cited by 6 | Viewed by 7604
Abstract
Aqueous and nonaqueous AOT/n-heptane reverse micelles where characterized by UV-Visible and fluorescence spectroscopy of AO. The study shows the presence of the dimer in aqueous reverse micelles which is not present in the nonaqueous systems. It seems that there is a conversion of [...] Read more.
Aqueous and nonaqueous AOT/n-heptane reverse micelles where characterized by UV-Visible and fluorescence spectroscopy of AO. The study shows the presence of the dimer in aqueous reverse micelles which is not present in the nonaqueous systems. It seems that there is a conversion of the dimer to monomer in the aqueous reverse micelles at high AOT concentration. In the nonaqueous systems, there is only partition of the monomer. The apparent constants of these processes were calculated. Full article
17 KiB  
Abstract
Synthesis of a Thienothiophene Conjugated Polymer
by Alejandra S. Diez, Silvana Saidman and Raúl O. Garay
Molecules 2000, 5(3), 555-556; https://doi.org/10.3390/50300555 - 22 Mar 2000
Cited by 13 | Viewed by 7786
Abstract
A new conducting polymer was prepared by chemical and electrochemical polymerization of 3,6-dimethylthieno[3,2-b]thiophene. The galvanostatic deposition afforded uniform, adherent and dark blue films of PDMTT. Electrochemical characterization by cyclic voltammetry showed that it can be repeatedly driven between the doped and undoped species [...] Read more.
A new conducting polymer was prepared by chemical and electrochemical polymerization of 3,6-dimethylthieno[3,2-b]thiophene. The galvanostatic deposition afforded uniform, adherent and dark blue films of PDMTT. Electrochemical characterization by cyclic voltammetry showed that it can be repeatedly driven between the doped and undoped species with a coulombic efficiency of nearly 100%. Full article
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Scheme 1

18 KiB  
Abstract
Integral Chemical Analysis of the Amaranth (Amaranthus greggii S. Wats)
by Silvia H. Pattacini, Gladis E. Scoles and Guillermo F. Covas
Molecules 2000, 5(3), 557-559; https://doi.org/10.3390/50300559 - 22 Mar 2000
Viewed by 6141
Abstract
The objective of this work was to obtain information on Amaranthus greggii S. Wats., related to its nutritional value, its agricultural application as leaf vegetable and for animal consumption. The following variables were analyzed: dampness, ashes, protein, mineral, ethereal extract (fat), brute fiber, [...] Read more.
The objective of this work was to obtain information on Amaranthus greggii S. Wats., related to its nutritional value, its agricultural application as leaf vegetable and for animal consumption. The following variables were analyzed: dampness, ashes, protein, mineral, ethereal extract (fat), brute fiber, oxalic acid, nitrates and carbohydrates. Full article
16 KiB  
Abstract
Catalytic Activity of MEL Zeolites Modified with Metallic Couples for the Conversion of Ethane
by Griselda Eimer, Pedro Girola, Lorena Tomas, Liliana B. Pierella and Oscar A. Anunziata
Molecules 2000, 5(3), 560-561; https://doi.org/10.3390/50300560 - 22 Mar 2000
Cited by 1 | Viewed by 5807
Abstract
The transformation of ethane into aromatic hydrocarbons over Zn-metal- containing zeolites at W/F=10 gh/mol and 550°C was studied in a flow reactor at atmospheric pressure. Zn-metal-zeolite modified the activation mode of the alkane, generating highly reactive intermediates and enhancing the aromatic selectivity. Full article
15 KiB  
Abstract
A Simple Method for N-Phenoxyethylation of Anilines
by G. P. Romanelli, J. L. Jios, O. Guaymas, R. Piovoso and J. C. Autino
Molecules 2000, 5(3), 562-563; https://doi.org/10.3390/50300562 - 22 Mar 2000
Cited by 1 | Viewed by 7743
Abstract
We wanted to search for new reaction conditions to prepare the title compounds, to be checked later in novel syntheses of heterocyclic compounds. To the best of our knowledge, there was no report in the literature of any well-established method for the preparation [...] Read more.
We wanted to search for new reaction conditions to prepare the title compounds, to be checked later in novel syntheses of heterocyclic compounds. To the best of our knowledge, there was no report in the literature of any well-established method for the preparation of N-(2-phenoxyethyl)anilines 1. Full article
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Scheme 1

17 KiB  
Abstract
First Synthesis of (20S) 3β,16β-Dihydroxy-5-pregnen-20,16-carbolactone (Diosgeninlactone)
by Andrea C. Bruttomesso and Eduardo G. Gros
Molecules 2000, 5(3), 564-565; https://doi.org/10.3390/50300564 - 22 Mar 2000
Cited by 2 | Viewed by 4928
Abstract
Diosgeninlactone (1), a natural product from Solanum vespertilio, was stereoselectively synthesized in high yield from 3β-hydroxy-5-androstene. Full article
14 KiB  
Abstract
Separation of the Pigment of an Amaranth
by Gladis Ester Scoles, Silvia Haydeé Pattacini and Guillermo Federico Covas
Molecules 2000, 5(3), 566-567; https://doi.org/10.3390/50300566 - 22 Mar 2000
Cited by 2 | Viewed by 6534
Abstract
It is known that current quality requirements require the utilization of natural colorants in the foods. The objective of the present work is to extract the pigment amaranthus from fresh leaves of Amaranthus hypochondriacus L. cv Don Pedro to characterize it through spectroscopic [...] Read more.
It is known that current quality requirements require the utilization of natural colorants in the foods. The objective of the present work is to extract the pigment amaranthus from fresh leaves of Amaranthus hypochondriacus L. cv Don Pedro to characterize it through spectroscopic techniques, to be used as natural colorants. Full article
18 KiB  
Abstract
Chemical Study of the Essential Oil of Mutisia Friesiana
by C. I. Viturro and J. De la Fuente
Molecules 2000, 5(3), 568-570; https://doi.org/10.3390/50300568 - 22 Mar 2000
Cited by 4 | Viewed by 7459
Abstract
The composition of essential oil of Mutisia friesiana (Asteracae) was studied. The oil is a complex system in which 127 compounds were identified. The major components are monoterpenes: b-phellandrene, (Z)-β-ocimene, α and β-pinene and sabinene. Full article
20 KiB  
Abstract
Bioactive Constituents of Conyza Albida
by A. Del V. Pacciaroni, L. Ariza Espinar, E. Mongelli, A. Romano, G. Ciccia and G. L. Silva
Molecules 2000, 5(3), 571-573; https://doi.org/10.3390/50300571 - 22 Mar 2000
Cited by 4 | Viewed by 6021
Abstract
Alkynes and spathulenol were isolated from Conyza albida (Asteraceae); some of the compounds were lethal against Artemia sp. and cytotoxic against KB cells. Full article
16 KiB  
Abstract
Development and Validation of a Chromatographic Method for the Analysis of Multicompound Pharmaceutical Preparations
by Carola Ferreyra, Cristina Ortiz and M. M. De Bertorello
Molecules 2000, 5(3), 574-575; https://doi.org/10.3390/50300574 - 22 Mar 2000
Cited by 1 | Viewed by 5508
Abstract
A reverse phase high performance liquid chromatographic assay was carried out for the simultaneous determination of two out of three active principles present in a pharmaceutical preparation. This method was developed to assess the quality of the product. Full article
15 KiB  
Abstract
Study of the Cytotoxic and Antifungal Activities of Neolignans 8.O.4´ and Structurally Related Compounds
by R. D. Enriz, F. Giannini, E. Correche, M. Carrasco, S. Zacchino and P. Matyus
Molecules 2000, 5(3), 576-577; https://doi.org/10.3390/50300576 - 22 Mar 2000
Cited by 1 | Viewed by 7413
Abstract
In the present work we report the antifungal and cytotoxic activities of a neolignan 8.O.4´series. The most active antifungal compounds show a significant cytotoxic effect which might be related. Full article
16 KiB  
Abstract
Kinetics of the Aromatic Nucleophilic Substitution Reaction Between 1-Fluoro-2,4-Dinitrobenzene and Perhydroazepine in Ethyl Acetate + Chloroform Solvent Mixtures
by P. M. Mancini, G. Fortunato and A. J. Terenzani
Molecules 2000, 5(3), 578-579; https://doi.org/10.3390/50300578 - 22 Mar 2000
Viewed by 6011
Abstract
In the present work, the kinetic behavior of the title reaction in ethyl acetate + chloroform solvent mixtures is studied. The experimental results are compared with previous findings. Full article
17 KiB  
Abstract
The Importance of Keto-Enol Forms of Arylpropanoids Acting as Antifungal Compounds
by F. Giannini, C. Devia, A. Rodríguez, R. Enriz, F. Suvire, H. Baldoni, R. Furlan and S. Zacchino
Molecules 2000, 5(3), 580-582; https://doi.org/10.3390/50300580 - 22 Mar 2000
Cited by 5 | Viewed by 6470
Abstract
We report here the importance of a keto-enol equilibrium of an arylpropanoid series acting as antifungal agents. An interesting relationship between ln MIC, ∆E enolization and net atomic charges was found. Two compounds were synthesized and their MIC evaluated in order to prove [...] Read more.
We report here the importance of a keto-enol equilibrium of an arylpropanoid series acting as antifungal agents. An interesting relationship between ln MIC, ∆E enolization and net atomic charges was found. Two compounds were synthesized and their MIC evaluated in order to prove the above relationship. Full article
308 KiB  
Abstract
Molecular Interactions Between the Active Sites of RGD (Arg-Gly-Asp) with its Receptor (Integrine)
by F. Suivre, R. Floridia, F. Giannini, A. Rodriguez, R. Enriz and E. Jauregui
Molecules 2000, 5(3), 583-584; https://doi.org/10.3390/50300583 - 22 Mar 2000
Cited by 3 | Viewed by 7492
Abstract
A study of the molecular interactions between the active sites of RGD (Arg-Gly-Asp) with it Receptor using simultaions is reported. Our calculations indicate that the guanidine-carboxylate complex is energetically favourd with respect to the guanidine-methyl tetrazole complex. Full article
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Figure 1

21 KiB  
Abstract
A Conformational Study of Flexible Cyclic Compounds (Hydrocarbon Rings of 9-12 Members)
by F. Suvire, S. Rodríguez, L. Santagata, A. Rodríguez and R. Enriz
Molecules 2000, 5(3), 585-586; https://doi.org/10.3390/50300585 - 22 Mar 2000
Cited by 2 | Viewed by 7335
Abstract
We report here a conformational study of cyclic flexible compounds (rings with 9-12 members). Two methods of systematic search for the minima were used. The results were compared with those obtained using other exploratory methods. Full article
16 KiB  
Abstract
Solvatochromic and Kinetic Response Models in (Ethyl Acetate + Chloroform or Methanol) Solvent Mixtures
by P. Mancini, C. Adam, A. Del C. Pérez and L. R. Vottero
Molecules 2000, 5(3), 587-588; https://doi.org/10.3390/50300587 - 22 Mar 2000
Cited by 1 | Viewed by 5858
Abstract
The present work analyzes the solvent effects upon the solvatochromic response models for a set of chemical probes and the kinetic response models for an aromatic nucleophilic substitution reaction, in binary mixtures in which both pure components are able to form intersolvent complexes [...] Read more.
The present work analyzes the solvent effects upon the solvatochromic response models for a set of chemical probes and the kinetic response models for an aromatic nucleophilic substitution reaction, in binary mixtures in which both pure components are able to form intersolvent complexes by hydrogen bonding. Full article
17 KiB  
Abstract
Catalytic Hydrogenation Reaction of Naringin-Chalcone. Study of the Electrochemical Reaction
by M. A. Nazareno, A. N. Giannuzzo, H. T. Mishima and B. A. López de Mishima
Molecules 2000, 5(3), 589-590; https://doi.org/10.3390/50300589 - 22 Mar 2000
Cited by 1 | Viewed by 9464
Abstract
The electrocatalytic hydrogenation reaction of naringin derivated chalcone is studied. The reaction is carried out with different catalysts in order to compare with the classic catalytic hydrogenation. Full article
28 KiB  
Abstract
Fluorescence Resonance Energy Transfer Using Spiropyran and Diarylethene Photochromic Acceptors
by L. Giordano, J. Macareno, L. Song, T. M. Jovin, M. Irie and E. A. Jares-Erijman
Molecules 2000, 5(3), 591-593; https://doi.org/10.3390/50300591 - 22 Mar 2000
Cited by 10 | Viewed by 6765
Abstract
We describe the preparation and photophysical characterization of two model compounds designed to test a new approach for the quantitative determination of Fluorescence Resonance Energy Transfer (FRET) in biological systems. The method enables modulation of FRET by exploiting the unique reversible spectral properties [...] Read more.
We describe the preparation and photophysical characterization of two model compounds designed to test a new approach for the quantitative determination of Fluorescence Resonance Energy Transfer (FRET) in biological systems. The method enables modulation of FRET by exploiting the unique reversible spectral properties of photochromic diarylethenes and spiropyrans to create switchable energy acceptors. Full article
19 KiB  
Abstract
Stereoselective Synthesis of 8-Trialkylstannylmenthols
by Sandra D. Mandolesi, Nelda N. Giagante, Verónica Dodero and Julio C. Podestá
Molecules 2000, 5(3), 594-595; https://doi.org/10.3390/50300594 - 22 Mar 2000
Cited by 1 | Viewed by 5609
Abstract
Trialkyltin menthones of type 2 are obtained selectively by 1,4-addition of trialkylstannyl lithium to (-)-pulegone. Reduction of 2 with borane in THF using as catalyst the reagent prepared from borane and (S)-valinol gave a mixture of the corresponding trialkyltin alcohols 3 (Me: 84%; [...] Read more.
Trialkyltin menthones of type 2 are obtained selectively by 1,4-addition of trialkylstannyl lithium to (-)-pulegone. Reduction of 2 with borane in THF using as catalyst the reagent prepared from borane and (S)-valinol gave a mixture of the corresponding trialkyltin alcohols 3 (Me: 84%; n-Bu: 90,6%) and 4 (Me: 16% and n-Bu: 9,4%). Full article
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Scheme 1

20 KiB  
Abstract
Polymerization Mechanism of α,α’-bis(Tetrahydrothiophenio)-β-xylene Dichloride
by Marcela Almassio and Raúl O. Garay
Molecules 2000, 5(3), 596-597; https://doi.org/10.3390/50300596 - 22 Mar 2000
Cited by 1 | Viewed by 6876
Abstract
A experimental study was performed regarding the influence of the base nature and solvent on the reactive intermediate concentration in the base-promoted bissulfonium salts polymerization. Such polymerization reaction is part of a synthetic procedure used to prepare conjugated polymers. In addition, a theoretical [...] Read more.
A experimental study was performed regarding the influence of the base nature and solvent on the reactive intermediate concentration in the base-promoted bissulfonium salts polymerization. Such polymerization reaction is part of a synthetic procedure used to prepare conjugated polymers. In addition, a theoretical study suggest that a one-electron transfer could be involved in the initiation step. Full article
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Scheme 1

14 KiB  
Abstract
Enantioselective Addition of Grignard Reagents to Aldehydes
by Pablo Englebienne, Hernan Schulz and Norma Nudelman
Molecules 2000, 5(3), 598-599; https://doi.org/10.3390/50300598 - 22 Mar 2000
Viewed by 7449
Abstract
The addition of Grignard reagents to aldehydes in the presence of chiral aminoalcohols shows a moderate enantioselectivity. The study carried out with a series of ligands allows the correlation between the structural characteristics and their reactivity. Full article
16 KiB  
Abstract
O-Sulfated Derivatives of Glucuronic Acid
by Mariano J. L. Castro, Natalia Salmaso, José Kovensky and Alicia Fernández Cirelli
Molecules 2000, 5(3), 600-601; https://doi.org/10.3390/50300600 - 22 Mar 2000
Cited by 2 | Viewed by 7600
Abstract
4-O-Substituted D-glucuronic acid derivatives were synthesized from D-glucose in order to study the regioselectivity of sulfation. Full article
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Figure 1

32 KiB  
Abstract
Synthesis and Computational Simulation of New Phosphorilated Sulfoximines with Insecticidal Activity
by M. E. Bellozas Reinhard and S. A. Licastrode
Molecules 2000, 5(3), 602-604; https://doi.org/10.3390/50300602 - 22 Mar 2000
Viewed by 6003
Abstract
New organophosphorus insecticides of dialkylsulphoximines derived with activity upon acetylcholinesterase were synthesized. The obtained compounds were characterized by NMR and IR, and anticholinesterase activity and toxicity was measured. A simulation through computer was done in order to establish the relationship between structure and [...] Read more.
New organophosphorus insecticides of dialkylsulphoximines derived with activity upon acetylcholinesterase were synthesized. The obtained compounds were characterized by NMR and IR, and anticholinesterase activity and toxicity was measured. A simulation through computer was done in order to establish the relationship between structure and activity. Full article
18 KiB  
Abstract
Phytochemical Study Conyza Sophiaefolia. Antiinflammatory Activity
by M. J. Simirgiotis, L. S. Favier, P. C. Rossomando, C. E. Tonn, A. Juarez and O. S. Giordano
Molecules 2000, 5(3), 605-607; https://doi.org/10.3390/50300605 - 22 Mar 2000
Cited by 1 | Viewed by 7903
Abstract
From the aerial parts of Conyza sophiaefolia a new alicyclic furan diterpene was isolated and characterized as an E-isomer in C6 of centipedic acid. In addition, the new clerodane type diterpene 12-epi-bacchotricuneatin A as well as two known related diterpenoids were identified. [...] Read more.
From the aerial parts of Conyza sophiaefolia a new alicyclic furan diterpene was isolated and characterized as an E-isomer in C6 of centipedic acid. In addition, the new clerodane type diterpene 12-epi-bacchotricuneatin A as well as two known related diterpenoids were identified. The flavone apigenine was also isolated. Structures were determined on the basis of spectroscopic evidence. Full article
28 KiB  
Abstract
Structure-Properties Relationship of Dimeric Surfactants from Butyl Glucosides
by Mariano J. L. Castro, José Kovensky and Alicia Fernández Cirelli
Molecules 2000, 5(3), 608-609; https://doi.org/10.3390/50300608 - 22 Mar 2000
Cited by 10 | Viewed by 6028
Abstract
Carbohydrate containing dimeric surfactants were synthesized starting from Dglucose. Three different spacers were used to link the sugar moieties. The critical micelle concentration (CMC) for these new compounds was determined. Full article
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Figure 1

17 KiB  
Abstract
Synthesis of 2,3-Butanedione over TS-1, Ti-NCl, TiMCM-41, Ti-Beta, Fe-Si, Fe-Beta and VS-1 Zeolites
by Andrea Beltramone, Marcos Gomez, Liliana Pierella and Oscar Anunziata
Molecules 2000, 5(3), 610-611; https://doi.org/10.3390/50300610 - 22 Mar 2000
Cited by 3 | Viewed by 6061
Abstract
The purpose of this work is the synthesis of 2,3-butanedione (diacetyl) by selective oxidation of 2-butanone (methyl ethyl ketone) in the presence of O2 and H2O2 30% as oxidants. All the tests were performed over several selective oxidation zeolite [...] Read more.
The purpose of this work is the synthesis of 2,3-butanedione (diacetyl) by selective oxidation of 2-butanone (methyl ethyl ketone) in the presence of O2 and H2O2 30% as oxidants. All the tests were performed over several selective oxidation zeolite catalysts, synthesized and characterized in our laboratory. Full article
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Figure 1

16 KiB  
Abstract
Reaction Mechanism for the Cyclization of 3-[γ,γ-Dimethylallyl]Coumaric Acid Methyl Ester in Dimethyl Sulfoxide (DMSO)
by E. J. Borkowski, C. E. Ardanaz, P. C. Rossomando and C. E. Tonn
Molecules 2000, 5(3), 612-613; https://doi.org/10.3390/50300612 - 22 Mar 2000
Viewed by 5039
Abstract
n/a Full article
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Scheme 1

18 KiB  
Abstract
Grindelic Acid Production in Grindelia Pulchella Cell Suspension Cultures Elicited with CuSO4
by X. E. Hernández, M. B. Kurina Sanz and O. S. Giordano
Molecules 2000, 5(3), 614-615; https://doi.org/10.3390/50300614 - 22 Mar 2000
Cited by 3 | Viewed by 4838
Abstract
n/a Full article
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Figure 1

15 KiB  
Abstract
Influence of Some Thia- or Azasubstituted Butyric Acid Derivatives on the Chemical Shift of the Benzene Ring Carbon Atoms
by Johannes Fröhlich, Fritz Sauter and Viktor Milata
Molecules 2000, 5(3), 616-619; https://doi.org/10.3390/50300616 - 22 Mar 2000
Cited by 1 | Viewed by 5284
Abstract
Eight thia- or azasubstituted butyric acid derivatives were prepared and the influence of these substituents on the chemical shifts of the benzene ring carbon atoms was studied. Full article
39 KiB  
Article
Synthesis of Crown Ethers Containing a Rubicene Moiety
by Mario Smet and Wim Dehaen
Molecules 2000, 5(3), 620-628; https://doi.org/10.3390/50300620 - 22 Mar 2000
Cited by 6 | Viewed by 7472
Abstract
A symmetrically disubstituted derivative of the highly fluorescing and photostable rubicene was incorporated in a macrocycle using high dilution conditions and a hydroxyrubicene was functionalized with a modified aminobenzo-15-crown-5. Full article
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Scheme 1

31 KiB  
Article
New Conjugated Systems Derived from Piperazine-2,5-dione
by Abdullah Mohamed Asiri
Molecules 2000, 5(3), 629-636; https://doi.org/10.3390/50300629 - 10 Mar 2000
Cited by 3 | Viewed by 8176
Abstract
The preparation of monoarylidene and both symmetrical and unsymmetrical bisarylidene derivatives of piperazine-2,5-dione is described. The use of 1,4-diacetylpiperazine-2,5-dione make it possible to prepare unsymmetrical bisarylidenes. The introduction of a dicyanomethylene moiety into the para position of one of the arylidene groups gave [...] Read more.
The preparation of monoarylidene and both symmetrical and unsymmetrical bisarylidene derivatives of piperazine-2,5-dione is described. The use of 1,4-diacetylpiperazine-2,5-dione make it possible to prepare unsymmetrical bisarylidenes. The introduction of a dicyanomethylene moiety into the para position of one of the arylidene groups gave a remarkable deepening in the colour of the resulting compounds 11 and 16. Full article
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Scheme 1

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