Molecules

124 KiB

Open AccessArticle

Synthesis of a New Scaffold: the 7H,8H-Pyrimido[1,6-b]pyridazin-6,8-dione Nucleus

by Franciszek Herold, Małgorzata Kałucka, Marek Król, Joanna Herold, Jerzy Kleps and Jadwiga Turło

Molecules 2007, 12(12), 2643-2657; https://doi.org/10.3390/12122643 - 30 Dec 2007

Cited by 1 | Viewed by 7148

Abstract

This paper describes a modified method of preparation of a number of α-aryl-α-(pyridazin-3-yl)-acetonitriles via the C-arylation reaction of the corresponding carbanionsof phenylacetonitriles using 3-chloropyridazine derivatives. KOH and DMSO were used inthe deprotonation process, which made the reaction very simple and safe to perform.Nitriles [...] Read more.

This paper describes a modified method of preparation of a number of α-aryl-α-(pyridazin-3-yl)-acetonitriles via the C-arylation reaction of the corresponding carbanionsof phenylacetonitriles using 3-chloropyridazine derivatives. KOH and DMSO were used inthe deprotonation process, which made the reaction very simple and safe to perform.Nitriles were obtained in the hydrolysis reaction to the corresponding α-aryl-α-(pyridazin-3-yl)-acetamide derivatives, which were next subjected to cyclization to afford the finalproducts. A number of new derivatives of 7H,8H-pyrimido[1,6-b]pyridazin-6,8-dione weresynthesized in the cyclocondensation reaction of respective α-aryl-α-(pyridazin-3-yl)-acetamides with diethyl carbonate in the presence of EtONa. The structure andcomposition of the new compounds were confirmed by IR, ¹H- and ¹³C- NMR analysesand by elemental C, H and N analysis. Full article

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364 KiB

Open AccessArticle

Synthesis and Antiviral Bioactivities of 2-Aryl- or 2-Methyl-3-(substituted- Benzalamino)-4(3H)-quinazolinone Derivatives

by Xingwen Gao, Xuejian Cai, Kai Yan, Baoan Song, Lili Gao and Zhuo Chen

Molecules 2007, 12(12), 2621-2642; https://doi.org/10.3390/12122621 - 27 Dec 2007

Cited by 62 | Viewed by 12267

Abstract

A simple and general method has been developed for the synthesis of various4(3H)-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H)-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, ¹H-NMR and ¹³C-NMR spectra. [...] Read more.

A simple and general method has been developed for the synthesis of various4(3H)-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H)-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, ¹H-NMR and ¹³C-NMR spectra. The title 2-aryl- or 2-methyl-3-(substituted-benzalamino)-4(3H)-quinazolinone compounds III-1~III-31 were found to possess moderate to good antiviral activity. Semi-quantitative PCR andReal Time PCR assays were used to ascertain the target of action of compound III-31against TMV. The studies suggest that III-31 possesses antiviral activity due to inductionof up-regulation of PR-1a and PR-5, thereby inhibiting virus proliferation and movementby enhancement of the activity of some defensive enzyme. Full article

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149 KiB

Open AccessArticle

Oxidative Degradations of the Side Chain of Unsaturated Ent-labdanes. Part II

by Luis Espinoza Catalán, Karen Catalán Marín, Héctor Carrasco Altamirano, Mauricio Cuellar Fritis and María Cristina Chamy

Molecules 2007, 12(12), 2605-2620; https://doi.org/10.3390/12122605 - 21 Dec 2007

Cited by 1 | Viewed by 9142

Abstract

A route for the degradation of the side chain of ent-labdane derivatives has beendevised, giving the useful synthon 2β,12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shallbe reported elsewhere. In addition we have synthesized the compound 2β,12-diacetoxy-8β,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), [...] Read more.

A route for the degradation of the side chain of ent-labdane derivatives has beendevised, giving the useful synthon 2β,12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shallbe reported elsewhere. In addition we have synthesized the compound 2β,12-diacetoxy-8β,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), which upon catalytic epoxide ringopening in alkaline or acid media gave rise in all cases to the formation of tricycliccompounds. Full article

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67 KiB

Open AccessArticle

Two New Triterpenoids from Photinia serrulata

by Yaling Song, Yuehu Wang, Qing Lu, Jinming Gao, Minggang Bi and Yongxian Cheng

Molecules 2007, 12(12), 2599-2604; https://doi.org/10.3390/12122599 - 20 Dec 2007

Cited by 4 | Viewed by 9974

Abstract

Two new triterpenoids, 2α,3β,11α,13β-tetrahydroxy-12-ketooleanan-28-oic acid(1) and 3β-hydroxy-12-keto-9(11)-ursen-28,13β-olide (2) were isolated from the leaves ofPhotinia serrulata. Their structures were identified by spectral methods. Compounds 1 and2 were assessed for cytotoxic activity against three human tumor cell lines (A-549, HCT-8,and BEL-7402), and they showed no [...] Read more.

Two new triterpenoids, 2α,3β,11α,13β-tetrahydroxy-12-ketooleanan-28-oic acid(1) and 3β-hydroxy-12-keto-9(11)-ursen-28,13β-olide (2) were isolated from the leaves ofPhotinia serrulata. Their structures were identified by spectral methods. Compounds 1 and2 were assessed for cytotoxic activity against three human tumor cell lines (A-549, HCT-8,and BEL-7402), and they showed no cytotoxic effects at concentrations up to 5μg/mL. Full article

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95 KiB

Open AccessArticle

Substituted N-Phenylpyrazine-2-carboxamides, Their Synthesis and Evaluation as Herbicides and Abiotic Elicitors

by Martin Doležal, Lenka Tůmová, Diana Kešetovičová, Jiří Tůma and Katarína Kráľová

Molecules 2007, 12(12), 2589-2598; https://doi.org/10.3390/12122589 - 20 Dec 2007

Cited by 25 | Viewed by 8436

Abstract

The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of [...] Read more.

The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of pyrazine derivatives as abiotic elicitors on the accumulation offlavonoids in a callus culture of Ononis arvensis (L.) were investigated. The most activeinhibitor of the oxygen evolution rate in spinach chloroplasts was 6-chloro-pyrazine-2-carboxylic acid (3-iodo-4-methylphenyl)-amide (2, IC₅₀ = 51.0 μmol·L^-1). The highestreduction of chlorophyll content in Chlorella vulgaris was found for 5-tert-butyl-N-(4-chloro-3-methylphenyl)-pyrazine-2-carboxamide (3, IC₅₀ = 44.0 μmol·L^-1). The maximalflavonoid production (about 900%) was reached after a twelve-hour elicitation processwith 6-chloropyrazine-2-carboxylic acid (3-iodo-4-methylphenyl)-amide (2). Full article

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89 KiB

Open AccessArticle

Synthesis of 1-Aryl-3-phenethylamino-1-propanone Hydrochlorides as Possible Potent Cytotoxic Agents

by Ebru Mete, Halise Inci Gul and Cavit Kazaz

Molecules 2007, 12(12), 2579-2588; https://doi.org/10.3390/12122579 - 12 Dec 2007

Cited by 10 | Viewed by 11722

Abstract

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4’-methyl-, 4’-methoxy-, 4’-chloro-, 4’-fluoro-, 4’-bromo-, 2’,4’-dichloro-, 4’-nitro-, 4’-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of [...] Read more.

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4’-methyl-, 4’-methoxy-, 4’-chloro-, 4’-fluoro-, 4’-bromo-, 2’,4’-dichloro-, 4’-nitro-, 4’-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. Theoptimum reaction conditions were investigated by changing the mol ratios of the reactants,the solvents and the acidity levels using 1 and 10 as representative targets. It was observedthat the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloridewas 1:1.2:1 (compared with a 2:2.1 ratio), and the most suitable reaction medium wasethanol containing concentrated hydrochloric acid (compared with only ethanol or nosolvent). This study may serve as a guide for the conditions of the reactions to synthesizecompounds having similar chemical structures. Full article

(This article belongs to the Special Issue Prodrugs)

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82 KiB

Open AccessArticle

Essential Oils of Satureja Species: Insecticidal Effect on Culex pipiens Larvae (Diptera: Culicidae)

by Antonios Michaelakis, Spiridon A. Theotokatos, Georgios Koliopoulos and Nikos G. Chorianopoulos

Molecules 2007, 12(12), 2567-2578; https://doi.org/10.3390/12122567 - 10 Dec 2007

Cited by 42 | Viewed by 9505

Abstract

The chemical composition of the essential oils of the wild growing plants of Greek S. spinosa L., S. parnassica subsp. parnassica Heldr.& Sart ex Boiss., S. thymbra and S. montana were determined by GC and GC/MS analysis. The larvicidal activities of the essential [...] Read more.

The chemical composition of the essential oils of the wild growing plants of Greek S. spinosa L., S. parnassica subsp. parnassica Heldr.& Sart ex Boiss., S. thymbra and S. montana were determined by GC and GC/MS analysis. The larvicidal activities of the essential oils were assayed against Culex pipiens biotype molestus. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major constituents of the oils, but their concentration varied greatly among the oils examined. The bioassay results indicated that the oils possess significant larvicidal activities and represent an inexpensive source of natural substances mixture that exhibit potentials for use to control the mosquito larvae. Full article

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Molecules, Volume 12, Issue 12 (December 2007) – 7 articles , Pages 2567-2657

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