Molecules

347 KiB

Open AccessArticle

New Synthetic Approaches to Multifunctional Phenazinium Salt Derivatives

by Inna Yu. Garipova and Vladimir N. Silnikov

Molecules 2003, 8(6), 505-519; https://doi.org/10.3390/80600505 - 30 Jun 2003

Cited by 4 | Viewed by 10454

Two different approaches are offered for the synthesis under mild conditions of disubstituted phenazinium and benzo[a]phenazinium salts. Direct nucleophilic substitutions by primary and secondary amines in quaternary phenazinium salts containing an additional positive charge in the aliphatic part of the molecule were carried [...] Read more.

Two different approaches are offered for the synthesis under mild conditions of disubstituted phenazinium and benzo[a]phenazinium salts. Direct nucleophilic substitutions by primary and secondary amines in quaternary phenazinium salts containing an additional positive charge in the aliphatic part of the molecule were carried out. The substitution proceeds successively in positions 2 and 7, which allows selective introduction of different substituents into the heterocycle. Direct nucleophilic substitution in quaternary 2-N-alkyl-acetamidophenazinium and 5-alkoxy-benzo[a]phenazinium salts with different amines can also serve as a convenient method for the introduction of two different substituents. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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62 KiB

Open AccessArticle

The Ring Transformation of 3-Methyl-5-nitropyrimidin-4(3H)-one

by Nagatoshi Nishiwaki, Mina Tamura, Kazushige Hori, Yasuo Tohda and Masahiro Ariga

Molecules 2003, 8(6), 500-504; https://doi.org/10.3390/80600500 - 30 Jun 2003

Cited by 4 | Viewed by 7583

Abstract

3-Methyl-5-nitropyrimidin-4(3H)-one readily reacts with carbonyl compounds to produce three kinds of ring transformations. The nitropyrimidinone behaves as the synthetic equivalent of activated diformylamine affording 3,5-difunctionalized 4-pyridones, 4,5-disubstituted pyrimidines and functionalized 4-aminopyridines. It also behaves like α-nitro-formylacetic acid to give 5,6-disubstituted 3-nitro-2-pyridones. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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209 KiB

Open AccessArticle

Novel Heteroatom-containing Vitamin D₃ Analogs: Efficient Synthesis of 1α,25-Dihydroxyvitamin D₃-26,23-lactam

by Yuko Kato, Yuichi Hashimoto and Kazuo Nagasawa

Molecules 2003, 8(6), 488-499; https://doi.org/10.3390/80600488 - 30 Jun 2003

Cited by 13 | Viewed by 8481

Abstract

Vitamin D₃ and its synthetic analogs are promising compounds for controlling various types of cell differentiation. In this article, we describe the synthesis of novel vitamin D₃ analogs containing heteroatoms in their side chains – so-called vitamin D3 lactam analogs – [...] Read more.

Vitamin D₃ and its synthetic analogs are promising compounds for controlling various types of cell differentiation. In this article, we describe the synthesis of novel vitamin D₃ analogs containing heteroatoms in their side chains – so-called vitamin D3 lactam analogs – via 1,3-dipolar cycloaddition reaction as a key step. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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149 KiB

Open AccessArticle

Synthesis of New Polyfused Heterocycles of Biological Importance by Means of Pd(0) Catalysis

by Gy. Hajós, Zs. Riedl, G. Timári, P. Mátyus, B. U. W. Maes and G. L. F. Lemière

Molecules 2003, 8(6), 480-487; https://doi.org/10.3390/80600480 - 30 Jun 2003

Cited by 12 | Viewed by 9520

Abstract

A general synthetic methodology employing heteroaryl-aryl Suzuki coupling is reviewed, by which 15 heteroaromatic ring systems of biological interest have been prepared. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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303 KiB

Open AccessArticle

Synthesis and Biological Evaluation of New 4,5-Disubstituted-Thiazolyl Amides, Derivatives of 4-Hydroxy-Piperidine or of 4-N-Methyl Piperazine

by A. Geronikaki, D. Hadjipavlou-Litina, C. Chatziopoulos and G. Soloupis

Molecules 2003, 8(6), 472-479; https://doi.org/10.3390/80600472 - 30 Jun 2003

Cited by 41 | Viewed by 9685

Abstract

4,5-disubstituted-thizolyl amides, derivatives of 4-hydroxy-piperidine and of 4-N-methyl piperazine, were synthesized and tested as anti-inflammatory agents. Log P values were theoretically calculated and experimentally determined. These compounds were tested for antioxidant activity, as hydroxyl radical scavengers and for their ability to interact with [...] Read more.

4,5-disubstituted-thizolyl amides, derivatives of 4-hydroxy-piperidine and of 4-N-methyl piperazine, were synthesized and tested as anti-inflammatory agents. Log P values were theoretically calculated and experimentally determined. These compounds were tested for antioxidant activity, as hydroxyl radical scavengers and for their ability to interact with stable 1,1-diphenyl-2-picryl hydrazyl free radical (DPPH). The effect of the synthesized compounds on inflammation, using the carrageenin induced mice paw edema model was studied. Both anti-inflammatory and antioxidant activities depended on some structural characteristics of the synthesized compounds. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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109 KiB

Open AccessArticle

Solid-Phase Synthesis of Methyl N-(pyrimidin-2-yl)glycinate

by Denis S. Ermolat'ev and Eugene V. Babaev

Molecules 2003, 8(6), 467-471; https://doi.org/10.3390/80600467 - 30 Jun 2003

Cited by 5 | Viewed by 7200

Abstract

A versatile method for the preparation of N-heteroaryl substituted aminoacid derivatives is suggested. The method avoids facile diketopiperazine formation. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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129 KiB

Open AccessArticle

Synthesis of 6-Nitroderivatives of Oxazolo[3,2-a]-pyridines and Their Reactions with Nucleophiles

by Alexander A. Bush and Eugene V. Babaev

Molecules 2003, 8(6), 460-466; https://doi.org/10.3390/80600460 - 30 Jun 2003

Cited by 8 | Viewed by 9039

Abstract

5-Nitro-2-pyridone can be selectively N-phenacylated, and the resulting phenacylpyridones I undergo cyclization to 6-nitrooxazolo[3,2-a]pyridinium salts II. These salts II readily react with ammonia and aliphatic amines leading to the products of pyridine ring opening - previously unknown 1-amino-2-nitro-4-(oxazole-2-yl)butadienes-1,3. Reaction of salts II with [...] Read more.

5-Nitro-2-pyridone can be selectively N-phenacylated, and the resulting phenacylpyridones I undergo cyclization to 6-nitrooxazolo[3,2-a]pyridinium salts II. These salts II readily react with ammonia and aliphatic amines leading to the products of pyridine ring opening - previously unknown 1-amino-2-nitro-4-(oxazole-2-yl)butadienes-1,3. Reaction of salts II with water lead to hydrolytic cleavage of the oxazole fragment. Full article

(This article belongs to the Special Issue Selected Papers from the Second Eurasian Meeting on Heterocyclic Chemistry: Heterocycles in Organic and Combinatorial Chemistry)

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