Molecules

91 KiB

Open AccessArticle

Reactivity of 4-tert-Butyldimethylsiloxy-1,2,3,6-tetrahydropyridines with Hydrazines

by Javier Figueroa, Esther Caballero, Pilar Puebla, Fernando Tomé and Manuel Medarde

Molecules 2006, 11(11), 929-939; https://doi.org/10.3390/11110929 - 30 Nov 2006

Cited by 5 | Viewed by 10223

The reactivity of 6-(nitrophenyl or trimethoxyphenyl)-4-tert-butyldimethyl- siloxy-1,2,3,6-tetrahydropyridine derivatives with hydrazines under acid conditions is described. The structure of the products isolated − hydrazones, pyrazolines or pyridazinones − depended on the conditions used. In addition, a systematic study of the reaction outcomes was carried [...] Read more.

The reactivity of 6-(nitrophenyl or trimethoxyphenyl)-4-tert-butyldimethyl- siloxy-1,2,3,6-tetrahydropyridine derivatives with hydrazines under acid conditions is described. The structure of the products isolated − hydrazones, pyrazolines or pyridazinones − depended on the conditions used. In addition, a systematic study of the reaction outcomes was carried out by introducing variations on the substituents of the tetrahydropyridine ring. Full article

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100 KiB

Open AccessArticle

Improving the Quality of Published Chemical Names with Nomenclature Software

by Gernot A. Eller

Molecules 2006, 11(11), 915-928; https://doi.org/10.3390/11110915 - 29 Nov 2006

Cited by 41 | Viewed by 12600

Abstract

This work deals with the use of organic systematic nomenclature in scientific literature, its quality, and computerized methods for its improvement. Criteria for classification of systematic names in terms of quality/correctness are discussed and applied to a sample set of several hundred names [...] Read more.

This work deals with the use of organic systematic nomenclature in scientific literature, its quality, and computerized methods for its improvement. Criteria for classification of systematic names in terms of quality/correctness are discussed and applied to a sample set of several hundred names extracted from the literature. The same structures are named with three popular state-of-the-art nomenclature programs – AutoNom 2000, ChemDraw 10.0, and ACD/Name 9.0. When comparing the results, all nomenclature tools show a significantly better performance than 'average chemists'. One program allows the generation not only of IUPAC names but also of CAS-like index names that are compared with the officially registered names. The scope and limitations of nomenclature software are discussed and a comparison of the programs' actual capabilities is given. Full article

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163 KiB

Open AccessArticle

Copper(II) Complexes with Ligands Derived from 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one: Synthesis and Biological Activity

by Tudor Rosu, Simona Pasculescu, Veronica Lazar, Carmen Chifiriuc and Raluca Cernat

Molecules 2006, 11(11), 904-914; https://doi.org/10.3390/11110904 - 17 Nov 2006

Cited by 82 | Viewed by 11123

Abstract

The synthesis of Cu(II) complexes derived from Schiff base ligands obtainedby the condensation of 2-hydroxybenzaldehyde or terephtalic aldehyde with 4-amino-antipyrine (4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one) is presented. The newlyprepared compounds were characterized by¹H-NMR, UV-VIS, IR and ESRspectroscopy. The determination of the antimicrobial activity of the [...] Read more.

The synthesis of Cu(II) complexes derived from Schiff base ligands obtainedby the condensation of 2-hydroxybenzaldehyde or terephtalic aldehyde with 4-amino-antipyrine (4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one) is presented. The newlyprepared compounds were characterized by¹H-NMR, UV-VIS, IR and ESRspectroscopy. The determination of the antimicrobial activity of the ligands and of thecomplexes was carried out on samples of Escherichia coli, Klebsiella pneumoniae,Acinetobacter boumanii, Pseudomonas aeruginosa, Staphylococcus aureus and Candidasp. The qualitative and quantitative antimicrobial activity test results proved that all theprepared complexes are very active, especially against samples of Ps. aeruginosa, A.Boumanii, E. coli and S. aureus. Full article

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145 KiB

Open AccessArticle

Facile Synthesis of 5, 6, 7, 8-Tetrahydropyrimido [4, 5-b]-quinoline Derivatives

by Yehya Mahmud Elkholy and Mohamed Abdelhamed Morsy

Molecules 2006, 11(11), 890-903; https://doi.org/10.3390/11110890 - 17 Nov 2006

Cited by 52 | Viewed by 10581

Abstract

2–Amino–4-phenyl–5,6,7,8–tetrahydroquinoline–3–carbonitrile (3) was synthesized by treating cyclohexanone (1) with 2–benzylidenemalononitrile (2) in the presence of ammonium acetate. The reactivity of compound 3 towards dimethylformamide dimethyl acetal (DMF-DMA), carbon disulfide, urea, thiourea, formamide, formic acid, acetyl chloride and isothiocyanate were studied. In addition, the [...] Read more.

2–Amino–4-phenyl–5,6,7,8–tetrahydroquinoline–3–carbonitrile (3) was synthesized by treating cyclohexanone (1) with 2–benzylidenemalononitrile (2) in the presence of ammonium acetate. The reactivity of compound 3 towards dimethylformamide dimethyl acetal (DMF-DMA), carbon disulfide, urea, thiourea, formamide, formic acid, acetyl chloride and isothiocyanate were studied. In addition, the antimicrobial activity of some selected derivatives is reported. Full article

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171 KiB

Open AccessArticle

Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

by Fátima C. Teixeira, Hélène Ramos, Inês F. Antunes, M. João M. Curto, M. Teresa Duarte and Isabel Bento

Molecules 2006, 11(11), 867-889; https://doi.org/10.3390/11110867 - 14 Nov 2006

Cited by 35 | Viewed by 13824

Abstract

A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH₂)_nCO₂R of different lengths (n = 0-6, 9, 10) are described.Nucleophilic substitution reactions on halo esters (X(CH₂)_nCO₂ [...] Read more.

A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH₂)_nCO₂R of different lengths (n = 0-6, 9, 10) are described.Nucleophilic substitution reactions on halo esters (X(CH₂)_nCO₂R) by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b) was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds. Full article

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65 KiB

Open AccessArticle

Revisiting the Reaction Between Diaminomaleonitrile and Aromatic Aldehydes: a Green Chemistry Approach

by Augusto Rivera, Jaime Ríos-Motta Ríos-Motta and Francisco León

Molecules 2006, 11(11), 858-866; https://doi.org/10.3390/11110858 - 11 Nov 2006

Cited by 18 | Viewed by 12292

Abstract

The reaction between diaminomaleonitrile (DAMN) and aldehydes and the resulting monoimines are well known. Since the standard reaction conditions involve the use of toxic solvents (typically methanol), we have sought to apply green chemistry principles to this reaction by either using water as [...] Read more.

The reaction between diaminomaleonitrile (DAMN) and aldehydes and the resulting monoimines are well known. Since the standard reaction conditions involve the use of toxic solvents (typically methanol), we have sought to apply green chemistry principles to this reaction by either using water as the solvent without any catalysts or employing “solvent-free” conditions. The monoimines derived from DAMN are of interest as precursors for obtaining different heterocyclic systems and linear polymers. The methodologies used have significant advantages with regards to cost and environmental considerations. Full article

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99 KiB

Open AccessArticle

Synthesis and Biological Evaluation of New 4β-5-Fu-substituted 4'-Demethylepipodophyllotoxin Derivatives

by Fu-Min Zhang, Xiao-Jun Yao, Xuan Tian and Yong-Qiang Tu

Molecules 2006, 11(11), 849-857; https://doi.org/10.3390/11110849 - 2 Nov 2006

Cited by 20 | Viewed by 8679

Abstract

A series of new 4β-5-Fu-substituted 4'-demethylepipodophyllotoxin derivatives were synthesized and evaluated, together with some previously prepared ones, for their cytotoxic activities against four tumor cell lines (HL60, P388, A549 and BEL7402). Three of these compounds exhibited superior in vitro anticancer activity against P388 [...] Read more.

A series of new 4β-5-Fu-substituted 4'-demethylepipodophyllotoxin derivatives were synthesized and evaluated, together with some previously prepared ones, for their cytotoxic activities against four tumor cell lines (HL60, P388, A549 and BEL7402). Three of these compounds exhibited superior in vitro anticancer activity against P388 and A549 than the reference compound etoposide. In addition, the partition coefficients (P) of all the new and previously synthesized derivatives were determined. Full article

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103 KiB

Open AccessArticle

Hydantoin Derivatives of L- and D-amino acids: Synthesis and Evaluation of Their Antiviral and Antitumoral Activity

by Zrinka Rajic, Branka Zorc, Silvana Raic-Malic, Katja Ester, Marijeta Kralj, Krešimir Pavelic, Jan Balzarini, Erik De Clercq and Mladen Mintas

Molecules 2006, 11(11), 837-848; https://doi.org/10.3390/11110837 - 1 Nov 2006

Cited by 61 | Viewed by 13297

Abstract

3,5-Disubstituted hydantoin (1,3-imidazolidinedione) derivatives 5a-h wereprepared by base induced cyclization of the corresponding N-(1-benzotriazolecarbonyl)-L-and D-amino acid amides 4a-h. Compounds 5a-h were evaluated for their cytostatic andantiviral activities. Among all the compounds evaluated, 3-benzhydryl-5-isopropylhydantoin (5a) showed a weak but selective inhibitory effect against vaccinia [...] Read more.

3,5-Disubstituted hydantoin (1,3-imidazolidinedione) derivatives 5a-h wereprepared by base induced cyclization of the corresponding N-(1-benzotriazolecarbonyl)-L-and D-amino acid amides 4a-h. Compounds 5a-h were evaluated for their cytostatic andantiviral activities. Among all the compounds evaluated, 3-benzhydryl-5-isopropylhydantoin (5a) showed a weak but selective inhibitory effect against vaccinia virus (EC₅₀ =16 μg/mL; selectivity index: 25). 3-Cyclohexyl-5-phenyl hydantoin (5g) showed inhibitoryactivity against cervical carcinoma (HeLa, IC₅₀ = 5.4 μM) and breast carcinoma (MCF-7,IC₅₀ = 2 μM), but also cytotoxic effects towards human normal fibroblasts (WI 38). On thecontrary, the 3-benzhydryl-5-phenyl substituted hydantoin derivative 5h showed moderateinhibitory activity towards HeLa, MCF-7, pancreatic carcinoma (MiaPaCa-2), lungcarcinoma (H 460) and colon carcinoma (SW 620) (IC₅₀ = 20−23 μM), but no effect on WI38. Full article

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104 KiB

Open AccessArticle

Regioselective Synthesis of Novel N₂- and N₄-Substituted 7-Methylpyrazolo[4,5-e][1,2,4]thiadiazines

by Xinyong Liu, Renzhang Yan, Niangen Chen, Wenfang Xu, Maria Teresa Molina and Salvador Vega

Molecules 2006, 11(11), 827-836; https://doi.org/10.3390/11110827 - 1 Nov 2006

Cited by 5 | Viewed by 10420

Abstract

The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one1,1-dioxide (5) was synthesized and its novel mono N₂- or N₄-substituted derivatives 6and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios ofNaH and alkyl halides. Based on the regioselective alkylation conditions found [...] Read more.

The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one1,1-dioxide (5) was synthesized and its novel mono N₂- or N₄-substituted derivatives 6and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios ofNaH and alkyl halides. Based on the regioselective alkylation conditions found a facileone-pot synthesis of N₂,N₄-disubstituted pyrazolo[4,5-e][1,2,4] thiadiazines 8 wasdeveloped. The structures of the newly synthesized compounds were confirmed by IR,¹H-NMR, ¹³C-NMR and MS spectral analysis. Full article

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Molecules, Volume 11, Issue 11 (November 2006) – 9 articles , Pages 827-939

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