Transformations of 2-trifluoromethylimidazo[4,5-b]pyridine

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1291–1292, September, 1992.     

Quaternization of 1H-imidazo[4,5-b]pyridine and 4-methyl-4H-imidazo[4,5-b]pyridine

Unsubstituted imidazo[4,5-b]pyridine adds methyl iodide to the pyridine N atom. Treatment of the resulting iodide with base forms 4-methyl-4H-imidazo[4,5-b]pyridine. This nucleophile can readily add methyl iodide to form only one salt, 1,4-dimethylimidazo[4,5-b]pyridinium iodide.L. M. Litvinenko Institute of Physical Organic Chemistry and Coal Chemistry, Ukraine Academy of Sciences, Donetsk 340114. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1232–1233, September, 1994. Original article submitted june 17, 1994.     

Syntheses of Oxazolo [4,5-b]pyridines and [4,5-d]pyrimidines

Oxazolo [4, 5-b] pyridines and [4, 5-d] pyrimidines and their 2-substituted compounds have been prepared respectively by condensation of orthoesters or thioimidates derivatives with 2-amino-3-hydroxypyridine and 4-amino-5-hydroxypyrimidine.     

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.     

Unexpected Result of Imidazo[4,5-b]pyridine Bromination

Russian Journal of Organic Chemistry -     

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 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.     

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.     

3,4-二氢-4-氧嘧啶并[4,5-b]喹啉类化合物的合成

Althuis等曾研究了一系列新的3,4-二氢-4-氧嘧啶并[4,5-b]喹啉-2-羧酸抗敏剂的结构与活性的关系^[1],得到比DSCG高400倍的药理活性.但对3-位N上取代基结构变化对药理活性的影响尚未见报道。     

2-formylimidazo[4,5-b]- and 2-formylimidazo[4,5-c]pyridines

The corresponding aldehydes were obtained by oxidation of N-substituted 2-methylimidazo-[4,5-b]- and 2-methylimidazo[4,5-c]pyridines with selenium dioxide. Some of their properties and transformations were studied.     

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.     

N-oxides of imidazo[4,5-b]quinoxalines and imidazo[4,5-b]pyrazines

The N-oxides and N,N-dioxides of methyl derivatives of imidazo[4,5-b]quinoxaline and imidazo[4,5-b]pyrazine were synthesized. The higher reactivity of the 2-methyl group in the N-oxides of 2-methylimidazo[4,5-b]quinoxaline as compared with the corresponding unoxidized derivatives was demonstrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1266–1270, September, 1972.     

Synthesis and Anticancer Activity of 1,3,4-Oxadiazole-oxazolo[4,5-b]pyridine Derivatives

Russian Journal of General Chemistry - A number of 1,3,4-oxadiazole incorporated oxazolo[4,5-b]pyridine derivatives has been synthesized, characterized and tested for anticancer activity against...