Reaction of 4-aminoimadazo[4.5-c]pyridin-2-ones with α-bromomethylketones

The reactions of 4-amino derivatives of imidazo[4.5-c]pyridin-2-ones with -bromomethylketones have been studied. Depending on the nature of the reagents and the reaction conditions, either 5-acylmethyl salts of the starting amine or 2-substituted imidazo[4.5-c]imidazo[1,2-a]pyridin-8-ones can be obtained. The latter compounds are also easily obtained by treatment of the 5-acylmethyl salts with alkali.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 227–232, February, 1986.     

Nouvelles voies d'accès à des aryl-4 thiéno[2,3-c]pyridines et à des aryl-7 thiéno[3,2-c]pyridines

4-Arylthieno[2,3-c]pyridines and 7-arylthieno[3,2-c]pyridines have been prepared by heating in polyphosphoric acid 2-(2-thenylamino>l-arylethanols or propanols and 2- 3-thenylamino>l-arylethanols or propanols, respectively.) Under the Beckmann rearrangement conditions, oximes of 4-aryl-4,5-dihydro-6H-cyclopenta[b]thiophen-6-one lead to 4-aryl-4,5- dihydro-6H-thieno[2,3-c]pyridin-7-one.     

Synthesis of new heteroaromatic systems: Naphth[2,1-e]imidazo[5,1-c]-1,2,4-triazines and benz[e]imidazo-[5,1-c]-1,2,4-triazines

Cyclization of azo compounds, synthesized from 5-diazoimidazoles and 2-naphthol or p-substituted phenols, into naphth[2,1-e]imidazo[5,1-c]-1,2,4-triazines and benz[e]imidazo[5,1-c]-1,2,4-triazines occurs only in the presence of p-toluenesulfonic acid. Imidazo[4,5-d]-1,2,3-triazines are also formed in this reaction when an amide substituent is present in the imidazole ring.Ural State Technical University, Ekaterinburg 620002, Russia: e-mail: mokr@htf.ustu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 540–546, April, 2000.     

Syntheses of 5-amino-3-(β-d-ribofuranosyl)imidazo [4,5-b] pyridin-7-one (1-deazaguanosine) and related nucleosides

The synthesis of 5-amino-3-(β-D-ribofuranosyl)imidazo[4,5-b ]pyridin-7-one (1-deazaguano-sine) has been accomplished by three different methods. The 6-thioguanosine analog 5-amino-3-(β-D-ribofuranosyl)imidazo [4,5-b ]pyridin-7-thione (1-deaza-6-thioguanosine) has been prepared in situ by a reduction of the corresponding disulfide. The synthesis of various nucleoside precursors of the above compounds by several condensation procedures are described. The procedures used to unequivocally determine the site of ribosylation and anomeric configuration are also discussed.     

Aza and deaza analogs of purine nucleosides (review)

Methods for the preparation of aza and deaza analogs of purine nucleosides, viz., nucleosides of imidazo[4,5-d]-v-triazines, imidazo[4,5-b]pyridines, and imidazo[4,5-c]pyridines, and their properties are described. References to the synthesis of nucleosides of imidazo[4,5-d]pyridazines, imidazo[4,5-c]pyridazines, and imidazo[4,5-b]pyrazines are also given.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 147–161, February, 1981.     

Studies in the imidazole series

Methods were developed for the synthesis of dihydro and tetrahydro derivatives of imidazo-[1,2-a]- and imidazo[1,2-c]pyrimidine and imidazo[2,1-b]-5-quinazolone from 2-amino- and 4-aminopyrimidines, 2-amino-4-quinazolones, and -haloethanols or 1,2-dihaloethanes. Dihydroimidazo[1,2-c]quinazoline, which was also obtained by cyclization of 4-(-hydroxyethylamino)-quinazoline, was synthesized by reaction of 4-chloroquinazoline with -haloethylamines.See [1] for communication LXXXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 834–836, June, 1976.     

Condensed imidazo-1,2,4-azines. 4. Synthesis of 1,4-Dihydroimidazo[1,5-c]-1,2,4-triazine derivatives

The reaction of 2-methyl-4(5)-nitro- and 2-methyl-4(5)-nitro-5(4)-bromoimidazoles with -halo ketones was investigated, during which a number of 1-acylmethyl-substituted 2-methyl-4-nitro- and 2-methyl-4-nitro-5-bromoimidazoles were obtained. 1,4-Dihydro derivatives of imidazo[1,5-c]-1,2,4-triazine were synthesized by reaction of the latter with hydrazine and its monosubstituted derivatives. The structures of the 1-acylmethyl-substituted 2-methyl-4-nitro-5-bromoimidazoles and 1,4-dihydro derivatives of imidazo[1,5-c]-1,2,4-triazine were confirmed by their IR, PMR, and mass spectra.See [1–3] for Communications 1–3, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 833–837, June, 1981.     

咪唑并吡啶类化合物的合成及其应用*

咪唑并吡啶类化合物具有与吲哚、氮杂吲哚等类似的特殊结构和良好的生物活性,在医药和农药工业有着广泛的应用,成为有机化学家和药物化学家的研究热点。咪唑并吡啶类化合物主要有咪唑并[4,5-b]吡啶、咪唑并[4,5-c]吡啶、咪唑并[1,2-a]吡啶和咪唑并[1,5-a]吡啶等4个类型。本文阐述了近年来咪唑并吡啶类化合物的合成研究进展和应用情况,主要介绍了咪唑并[4,5-b]吡啶和咪唑并[4,5-c]吡啶这两类化合物的合成方法和在医药及农药领域的应用。     

Studies on antiulcer drugs. III. Synthesis and antiulcer activities of imidazo[1,2-a]pyridinylethylbenzoxazoles and related compounds. A novel class of histamine H2-receptor antagonists.

A series of imidazo[1,2-a]pyridinylalkylbenzoxazole derivatives was synthesized and tested for histamine H2-receptor antagonist, gastric antisecretory and antiulcer activities. Some of 2-amino-6-[2-(imidazo[1,2-a]pyridin-2-yl)ethyl]benzoxazole derivatives were found to have good pharmacological activities. Among them, 2-amino-6-[2-(7-methoxy-3-methylimidazo[1,2-a]pyridin-2-yl)ethyl] benzoxazole (II-11) and 2-acetamido-6-[2-(7-methylimidazo[1,2-a]pyridin-2-yl)ethyl] benzoxazole (II-38) showed potent antisecretory and cytoprotective activity. The structure-activity relationships of these compounds are discussed.     

Synthesis of imidazo[4,5-c]pyrazoles via copper-catalyzed amidine cyclization

A new synthetic approach to 4-substituted imidazo[4,5-c]pyrazoles is proposed on the basis of the N'-(4-halopyrazol-5-yl)amidine cyclization under the conditions of copper-catalyzed cross-coupling reactions. Using 5-aminopyrazoles and copper catalysts as starting materials, the method is inexpensive and convenient and allows a wide range of substituents at all positions of the imidazo[4,5-c]pyrazole nucleus.     

Lawesson's reagent-initiated domino reaction of aminopropenoyl cyclopropanes: synthesis of thieno[3,2-c]pyridinones

A convenient and efficient synthesis of substituted 2,3-dihydrothieno[3,2-c]pyridin-4(5H)-ones has been developed and relies upon a domino reaction of dimethylaminopropenoyl cyclopropanes initiated by Lawesson's reagent. A mechanism involving regioselective thionation, ring-enlargement, and an intramolecular aza-cyclization sequence is proposed. This protocol was utilized as a one-pot route to thieno[3,2-c]pyridin-4(5H)-ones with DDQ as an oxidant.     

Synthesis of 1,4-dihydroimidazo[5,1-c]-1,2,4-triazin-4-ones and imidazo[5,1-c]-1,2,4-triazoles

Azo compounds obtained by the coupling of 5-diazoimidazoles with diethyl esters of nitro-, chloro-, bromo-, and acetylaminomalonic acids under conditions of base catalysis are cyclized to give 1,4-dihydroimidazo[5,1-c]-1,2,4-triazin-4-ones or imidazo[5,1-c]-1,2,4-triazoles. The chloro, bromo, and nitro groups in the bicyclic products are readily replaced by action of nucleophiles. The imidazotriazinones are converted to chloroimidazotriazines by reaction with thionyl chloride or phosphorus oxychlorideUrals State Technical University-UPI, 620002 Yekaterinburg, Russia Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1544–1553, November, 1999.     

The synthesis of novel 1-hetarylmethylidene-4-sulfanylfuro-[3,4-c]pyridin-3(1H)-ones

Chemistry of Heterocyclic Compounds - 1-Hetarylmethylidene-4-sulfanylfuro[3,4-c]pyridin-3-ones were accessed from 4-thioxo-4,5-dihydrofuro[3,4-c]pyridin-3(1H)-one employing a condensation reaction...     

Synthesis and biological study of novel 5-{(4-(6,7-dihydrothieno-[3,2-c]pyridin-5(4H)-ylsulfonyl)phenylamino)-methyl}quinolin-8-ol and its metal complexes

A novel 5-((4-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-ylsulfonyl)phenylamino)methyl)quinolin-8-ol(HTPSMQol) was synthesized by optimized reaction of 4-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-ylsulfonyl)aniline with 5-chloromethyl-8-hydroxy-quinoline hydrochloride(CMHQ).Also complexes of HTPSMQol were prepared by using various M(Ⅱ) metal salts.All compounds were analyzed by spectroscopic techniques and screened against various strains of microorganisms.The results showed higher antimicrobial activity of HTPSMQol compared to its metal complexes and comparable with Ciprofloxacin.     

Thionation of imidazopyridines

Direct thionation of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines results in the formation of their 2-thioxo derivatives, usually in high yield. The thione structure of the imidazopyridines obtained has been confirmed from their IR spectra in the solid state and in solution. The general nature of the thionation of imidazole, benzimidazole, imidazo[4,5-b]pyridine, imidazo[4,5-c]pyridine, and purine has been noted as one of the distinctive chemical properties of compounds in this series of nitrogen heterocycles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 799–804, June, 1988.     

Regiospecific synthesis of 3-substituted imidazo[1,2-a]pyridines,imidazo[1,2-a]pyrimidines,and imidazo[1,2-c]pyrimidine

3-Substituted imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[1,2-c]pyrimidine were obtained regiospecifically in yields of 35-92% in one pot by reaction of 2-aminopyridines or 2-(or 4-)aminopyrimidines, respectively, with 1,2-bis(benzotriazolyl)-1,2-(dialkylamino)ethanes.     

Synthesis of azinoazole structural isomers by photocyclization

Irradiation of 2-chloro-N-(pyridin-2-yl)pyridin-3-amine and N-(2-chloropyridin-3-yl)-4,6-dimethyl-pyrimidin-2-amine in aqueous-alcoholic solution gave new azinoazole derivatives, 6-chlorodipyrido-[1,2-a:5′,4′-d]imidazole and 1,3-dimethylpyrido[3′,2′:4,5]imidazo[1,2-a]pyrimidine, respectively.     

Synthesis of 4-Halo-3-isopropoxyfuro[3,4-с]-pyridin-1(3H)-ones

Russian Journal of Organic Chemistry - The reaction of 4-halo-3-hydroxyfuro[3,4-c]pyridin-1(3H)-ones with propan-2-ol leads to the formation of 4-halo-3-isopropoxyfuro[3,4-c]pyridin-1(3H)-ones. The...     

Synthesis of disubstituted imidazo[4,5-b]pyridin-2-ones

Regioselective palladium-catalyzed amination of 2-chloro-3-iodopyridine followed by a subsequent palladium-catalyzed amination leads to 2,3-diaminopyridines. Treatment with triphosgene affords highly functionalized unsymmetrical imidazo[4,5-b]pyridin-2-ones in just three synthetic steps. A two-step synthesis of pseudosymmetrically disubstituted imidazo[4,5-b]pyridin-2-ones, 1,4-disubstituted pyrido[2,3-b]pyrazinediones, and 1,3-disubstituted thiadiazolo[3,4-b]pyridin-2-ones is also described.     

Synthesis and some reactions of 4-nitro derivatives of imidazo[4,5-c]pyridin-2-ones

Imidazo[4,5-c]pyridine and its N-methyl derivatives do not undergo nitration, but the 2-oxo derivatives of these compounds are easily nitrated when heated. Some properties of the resulting 4-nitroimidazo[4,5-c]pyridin-2-ones have been studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 97–102, January, 1986.