Synthesis and Properties of 1,3-Diaryl-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium Bromides

It has been established that the condensation of 3-(4-methoxyphenylamino)-5,6-dihydro-2H-1,4-oxazine with substituted phenacyl bromides occurs at the exocyclic nitrogen atom with formation of 3-aryl-3-hydroxy-1-(4-methoxyphenyl)-2,5,6,8-tetrahydro-3H-imidazo[2,1-c]-1,4-oxazinium bromides. By treatment of the latter with acetic anhydride 3-aryl-1-(4-methoxyphenyl)-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium bromides are formed. The structures of the compounds synthesized were determined via ¹H NMR spectroscopy and X-ray diffraction.     

Synthesis of novel imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines

Several 1 1-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines have been used as starting material to prepare a number of derivatives of 9H-imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines and 10H-pyrimido[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepines. The imidazole nucleus was built by reaction of amidines with ethyl bromopyruvate or aminoacetaldehyde dimethylacetal. Several derivatives of imidazo[1,2-a]pyrrolo[2,1-c][1,4]benzodiazepine have been prepared by formylation of the pyrrole ring followed by formation of thioamides. Condensation of 11-amino-5H-pyrrolo[2,1-c][1,4]benzodiazepines with diethyl ethoxymethylenemalonate afforded intermediate diesters which were transformed into the corresponding 10H-pyrimido[1,2-a]pyrrolo[2,1-c]-benzodiazepines.     

Synthesis and reactions of 2,4-disubstituted benzo[b]furano-, benzo[b]thieno- and indolo[3,2-d]-1,3-oxazinium salts

Under acid catalyzed acylation 3-acetamidobenzo[b]furan, -benzo[b]tkiophene, and indole undergo heterocyclization to condensed 1,3-oxazinium salts. Treatment of the salts with ammonium acetate in acetic acid gives the corresponding benzo[b]furano- and benzo[b]thieno[3,2-d]pyrimidines and 2-acetyl-3-acetamidoindole gives pyrimido [5,4-d] indole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1569–1571, November, 1990.     

Synthesis of 5H-imidazo[2,1-c]pyrrolo[1,2-a][1,4]benzodiazepine

We have synthesized 5H-imidazo[2,1-c]pyrrolo[1,2-a][1,4]benzodiazepine 1 in five steps from 1-(2-amino-methylphenyl) pyrrole 4 . Amidino derivatives 11-12 have also been prepared.     

Synthesis of substituted indolo[1,2-c]quinazolines

It was established that N-acetylindoxyl arylhydrazones are converted to 12-acetamidoindolo[1,2-c]quinazolines in acetic acid in the presence of acetic anhydride, evidently through a step involving the formation of arylhydrazoindole derivatives. A new method for the synthesis of 12-acetamidoindolo[1,2-c]quinazolines from N,O-diacetylindoxyls and arylhydrazines is proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 832–835, June, 1979.     

Synthesis and some properties of N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]pyrazinones

Reactions of methyl 2-(2-formyl-1H-pyrrol-1-yl)alkanoates with unsubstituted aliphatic 1,2-, 1,3-, and 1,4-diamines gave N-unsubstituted pyrrolo[2,1-c]-1,3-diazacycloalkano[1,2-a]-pyrazinones. Some of them show ring-chain tautomerism. Transformations of these compounds led to a number of novel heterocyclic systems: 2,10-dihydro-3H,5H-imidazo[1,2-a]-pyrrolo[1,2-d]pyrazines, 2,3,4,11-tetrahydro-6H-pyrrolo[1??,2??:4,5]pyrazino[1,2-a]pyrimidines, 1,2,3,5,6,10b-hexahydroimidazo[1,2-a]pyrrolo[2,1-c]pyrazines, 1,3,4,6,7,11b-hexahydro-2H-pyrrolo[2??,1??:3,4]pyrazino[1,2-a]pyrimidines, and 2,3,4,5,6,7-hexahydro-1H-pyrrolo[2,1-c]-[1,4,7]triazacycloundecin-8(9H)-one.     

4-Substituted-4H-pyrrolo[2,1-c] [1,4]benzoxazines

The condensations of 1-(2-hydroxyphenyl) pyrroles with a variety of carbonyl compounds are shown to give new 4-substituted-4H-4-methylpyrrolo[2,1-c][1,4]benzoxazines. Some of the products were further functionalized. The ir, uv, and pmr spectra of the title heterocyclic system are discussed. Reaction of 1-(2-hydroxyphenyl) pyrrole with dimethyl acetylenedicarboxylate yielded dimethyl 3-(2-hydroxyanilino) phthalale; a mechanistic rationale which accounts for the result involves a rearrangement of the hypothetical Diels-Alder adduct.     

Synthesis of indolo[2,3-c]coumarins and indolo[2,3-c]quinolinones via microwave-assisted base-free intramolecular cross dehydrogenative coupling

A microwave-assisted base-free intramolecular cross dehydrogenative coupling (CDC) of 3-aniline substituted coumarins and quinolinones have been developed. A broad range of indolo[2,3-c]coumarins and indolo[2,3-c]quinolinones can be easily afforded in good to high yields (up to 93%) under palladium catalysis. The method is among the most straightforward and convenient ways to access these fused polyheterocycles.     

Synthesis of substituted indano[2,1-c]piperidines

Substituted indano[2,1-c]piperidines were obtained by selective hydrogenation over Re₂S₇ and also by reduction with sodium in alcohol of 3-methyl-2-azafluorene and its derivatives. The geometrical isomers of the products were isolated and characterized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1379–1383, October, 1973.     

Synthesis of thieno[3,4-c] and thieno[3,2-c][2,1]benzothiazepines

Starting from [4,3-c] and [3,2-c] methyl chlorosulfonylthiophenecarboxylates the synthesis of ketones 7 and 8 is described. These compounds are the first two representatives of the new thieno[3,4-c] and thieno-[3,2-c][2,1]benzothiazepine ring systems. The formation of methyl 3-chlorosulfonylthiophene-2-carboxy-late is also revised.     

Synthesis of 1,4,6,7-tetrahydroimidazo[2,1-c] [1,2,4] triazines

From 2-methylthioimidazoline and phenaeylbromides in DMF there were obtained the 2-(2-methylthio-2-imidazolin-1-yl)aeetopht'nones 3a-3f . From these the substituted 3-phenyl-1,4,6,7-tetrahytlroimidazo[2,1-c][1,2,4]triazines 4a-4n were prepared upon reaction with hydrazine and methylhydrazine respectively. Compound 4a was degraded to the triazine 6. From the (2-methylthio-2-imidazolin-l-yl)-acetie acid ester 10, the imidazo[2,1-c] [1,2,4]triazines 11a-11c were prepared. Selective ethylation on the oxygen was achieved with 11b in the presence of Meerwein' salt.     

Synthesis and some reactions of selenopheno[2,3-c]pyrylium salts

The catalytic acylation and subsequent heterocyclization of -acetonyl derivatives of selenophene have been investigated. Methods have been proposed for the synthesis of new heteroaromatic systems: salts of the selenopheno[2,3-c]pyrylium cation and of selenopheno[2,3-c]pyridine. Methods have been developed for the synthesis of selenophene-3-carbaldehydes and 3-acetonylselenophenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 918–922, July, 1973.     

Synthesis and cycloaddition reactions of ethyl glyoxylate imines. Synthesis of substituted furo-[3,2-c]quinolines and 7H-indeno[2,1-c]quinolines

Lewis acid catalyzed cycloaddition reactions of ethyl glyoxylate imines to dihydrofuran and indene yield substituted hexahydrofuro[3,2-c]- and tetrahydro-7H-indeno[2,1-c]quinolines respectively. Oxidation of the adducts with 2,3-dichloro-5,6-dicyanobenzoquinone affords the corresponding aromatic compounds.     

Synthesis of (1H)-3,4-Dihydropyrrolo[2,1-c][1,4]oxazin-1-one Derivatives

It has been found that some acyl derivatives of 1,2,3,4-tetrahydro-1-indolizin-1-one 1and (1H)-3,4-dihydropyrrolo[1,2-a]pyrazin-1-one 2 show remarkable anti-inflammatory and analgesic activities1,2. The interest in extending the study of structure-activity relationships and search of new potent anti-inflammatory and analgesic agents led us to design and synthesize (1H)-3,4-dihydropyrrolo[2,1-c][1,4]oxazin-1-one 3 derivatives. NO 1 NNHO2 87654321ONO3 A few examples of the p…     

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.