Synthesis of isoxazolo[5,4-b]pyridine derivatives (microreview)

Chemistry of Heterocyclic Compounds - The microreview summarizes the data on heterocyclization methods leading to the formation of isoxazolo[5,4-b]-pyridines published over the last 5 years. The...     

Isothiazolo[5,4-b]pyridine analogs of nalidixic acid

The synthesis and antibacterial evaluation of a number of isothiazolo[5,4-b]pyridine isosteres of nalidixic acid are described.     

Some derivatives of pyrimido [5,4-b]quinoline

10-Chloro-2,4-dioxo derivatives of pyrimido[5,4-b]quinoline have been synthesized, and nucleophilic substitution reactions in these compounds have been studied.     

Recent progress in the chemistry of heterocycles incorporated oxazolo[4,5-b]pyridine and oxazolo[5,4-b]pyridine skeletons

Abstract

The present study describes recent advances in the chemistry of heterocycles incorporated oxazolo[4,5-b]pyridine and oxazolo[5,4-b]pyridine skeletons. The main sections included the synthesis of the investigated compounds from readily accessible aminopyridinol derivatives or aminopyridines. The reactivity of substituents attached to ring carbon or nitrogen atoms were discussed. In addition, the synthetic and biological evaluation of the inspected oxazolopyridines were highlighted. The purpose of this review is to discuss the chemistry of the title so far. The present study will support researchers in the fields of organic and medicinal chemistry to design and develop new protocols for the construction of new biological components.     

Polymethine dyes — Benzofuro[2,3-b]pyridine and selenonaphtheno[2,3-b]pyridine derivatives

Polymethine dyes — benzofuro[2,3-b]pyridine and selenonaphtheno[2,3-b]pyridine derivatives — were synthesized, and their spectral properties are discussed. Replacement of a vinylene group by an oxygen or selenium atom in one benzene ring of the 2-benzo[h]quinoline residue in the cyanines causes a large bathochromic shift of the absorption maxima of the dyes as compared with replacement by a sulfur atom. The dyes derived from benzofuro[2,3-b]pyridine derivatives are more deeply colored than the derivatives of both thionaphtheno[2,3-b]-pyridine and selenonaphtheno[2,3-b]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp.1611–1614, December, 1972.     

Synthesis of 3-amino-5H-pyrimido[5,4-b]indol-4-one derivatives

Starting with ethyl 3-aminoindole-2-carboxylate, the synthesis of 3-amino-5H-pyrimido[5,4-b]indole-2,4-dione 5 , 3-amino-5H-pyrimido[5,4-b]indol-4-one 10 and some related compounds is described. Preliminary results about the inhibition of platelet aggregation by these compounds is reported.     

Synthesis of 3-oxoisothiazolo[5,4-b] pyridines

3-Oxoisothiazolo[5,4-b]pyridines were synthesized for the first time by the reaction of 3-cyanopyridine-2-thiones or bis(3-cyanopyridyl) disulfides with concentrated sulfuric acid. It is demonstrated that 3-carbamoylpyridine-2-thiones are formed as intermediates. The 3-oxoisothiazolopyridines were converted to 3-bromoisothiazolopyridines and pyridine-2-thiones. The bromination of pyridine-2-thione was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 508–512, April, 1982.     

Synthesis of aromatic pyrazolo[4,5-b]pyridine derivatives

Cyclocondensation of chalcones with 5-amino-3-methyl-1-phenylpyrazole leads to the formation of 2,4-diaryl-5-methyl-7-phenyl-3,4-dihydropyrazolo-[4,5-b]pyridines, which undergo aromatization upon treatment with N-bromosuccinimide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1247–1251, September, 1987.     

Tautomerism of some imidazo[4,5-b]pyridine derivatives

It was shown by means of UV and IR spectroscopy and the ionization constants that the tautomeric equilibrium of 2-amino- and 2-mercapto derivatives of 3-methyl-3H-imidazo[4,5-b]pyridine is shifted to favor the amino and thione forms, respectively.     

Synthesis of 2-substituted 3-oxoisothiazolo[5,4-b]pyridines

Starting with 2-chloro-3-pyridinecarboxylic acid 1 , three different routes to prepare 3-oxoisothiazolo-[4,5-b]pyridines 10 were studied.     

Convenient synthesis and anticancer evaluation of novel pyrazolyl-thiophene,thieno[3,2-b]pyridine,pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine derivatives

The newly synthesized 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was utilized as a precursor for the synthesis of pyrazolyl-thiophene derivative, which undergoes cyclization upon treatment with benzaldehyde derivatives to provide pyrazolo[3,4-d]thieno[3,2-b]pyridines. Basic treatment of pyrazolyl-thiophene derivative with phenyl isothiocyanate followed by subsequent addition of chloroacetone and/or ethyl bromoacetate yielded the thiazolylidene-pyrazolyl thiophenes. In addition, the building block 3-(3-amino-5-(phenylamino)-4-(phenylcarbamoyl)thiophen-2-yl)-3-oxopropanoate was converted into the corresponding thieno[3,2-b]pyridine compounds through its reactions with (DMF-DMA) and/or heating in sodium ethoxide. Moreover, the reaction of 7-hydroxy-5-oxo-N-phenyl-2-(phenylamino)-4,5-dihydrothieno[3,2-b]pyridine-3-carboxamide with 2-arylidenemalononitrile produced the new annulated pyrano[2,3-d]thieno[3,2-b]pyridines. The prepared thiophene-based compounds were evaluated against HepG2, PC3, and MCF-7 cancer cells, and normal fibroblast cell (WI38). The pyrazolo[3,4-d]thieno[3,2-b]pyridine and pyrano[2,3-d]thieno[3,2-b]pyridine compounds substituted with chlorophenyl group presented promising cytotoxic activities against HepG2 cancer cell line without any human toxicity. Docking study for the synthesized thiophene compounds delivered valuable insights about the binding interactions with the crystal structure of NS5B enzyme with PDB ID (4TLR).     

Quaternization centers of N-methyl derivatives of imidazo[4,5-b]pyridine

It is shown that quaternization of isomers of 1-methylimidazo[4,5-b]pyridine and 3-methyl-imidazo[4,5-b]pyridine proceeds at different reaction centers — at the nitrogen atom of the imidazole ring in the first case and at the nitrogen atom of the pyridine ring in the second case.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1686–1688, December, 1973.     

1H-pyrazolo[3,4-d]thieno[2,3-b]pyridine and its derivatives

The synthesis of the parent ring system and some of the derivatives of 1H-pyrazolo[3,4-d]thieno[2,3-b]pyridine are described.     

Green synthetic approach toward new chromeno[4,3-b]quinoline and chromeno[4,3-b]pyridine derivatives

Chemistry of Heterocyclic Compounds - A facile, convenient, and efficient synthesis of new chromeno[4,3-b]quinoline and chromeno[4,3-b]pyridine derivatives has been accomplished via one-pot...     

Polymethine dyes - 4-substituted furo [2,3-b]- and selenopheno[2,3-b]pyridine derivatives

Polymethine dyes that are 4-substituted furo[2, 3-b]pyridine and selenopheno-[2, 3-b] pyridine derivatives were synthesized. It was shown that replacement of the vinylene group in the benzene ring of a 4-quinoline heteroresidue in the cyanine dyes by an oxygen or selenium atom causes a greater hypsochromic shift in their absorption maxima than replacement by a sulfur atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 56–60, January, 1976.     

Synthesis of New Imidazo[4,5-b]pyridine Derivatives

New imidazo[4,5-b]pyridine derivatives with various substituents in the 2-position (,-unsaturated ketones, imines, ²-pyrazolines, pyrimidines, 1,2,3,4-tetrahydropyrimidines) and derivatives of the new pyrido[3',2':4,5]imidazo[1,2-d][1,2,4]triazine ring system were synthesized. Biological data for selected compounds are presented.     

Synthesis of New Thieno[2,3-b:5,4-c']dipyridines

We describe the formation of thieno[2,3-b:5,4-c]dipyridines from 5,6-dihydropyridine-2(1H)-thiones. The two-step reaction mechanism was revealed by isolation of an intermediate. The oxo and thioxo groups of the obtained tricyclic compounds were hydrogenated selectively. The structures of all new compounds were elucidated by NMR experiments.