A. V. Varlamov

Heterocyclization of tropinone oximes and 3-methyl-3-azabicyclo[3.3.1.]-nonan-9-one with acetylene in a superbasic medium

Tropinone oxime reacts with acetylene in syperbasic medium to form ordinary products of heterocyclization. The oxime of 3-methyl-3-azabicyclo[3.3.1]nonan-9-one does not undergo heterocyclization due to the impossibility of a [3,3]-sigmatropic rearrangement of its vinyl ether.

New method for the synthesis of pyrido[1,2-a]benzimidazole

A catalytic method for the conversion of α-(phenylamino)pyridines to pyrido-[1,2-a]benzimidazoles was developed.

Tandem cleavage of 2,3,5-trimethyl 7-trifluoroacetyl-1,2,3,4-tetrahydro-pyrrolo[1,2-c]pyrimidine by activated alkynes, caused by Michael addition of a tertiary nitrogen atom to a triple bond

The interaction of 7-trifluoroacetyltetrahydropyrrolo[1,2-c]pyrimidine with acetylenedicarboxylic ester (DMAD) and ethyl propiolate in acetonitrile and alcohols has been studied. It was established that DMAD splits pyrrolopyrimidine at the aminal fragment in acetonitrile and methanol with the formation of 1-H-and 2-(N-dimethoxycarbonylvinyl-N-methyl)aminoethyl-1-methoxymethyl-3-methyl-5-trifluoroacetylpyrroles. In acetonitrile ethyl propiolate splits pyrrolopyrimidine both at the aminal fragment and at the C(3)-N(2) bond (Hofmann reaction), but in ethanol only at the C(3)-N(2) bond with the formation of 2-propenylpyrroles.

Heterocyclization of oximes of 3,5-dimethyl(1,3,5-trimethyl)-2,6-diphenylpiperid-4-ones and n-benzylpyrrolid-3-ones with acetylene in a superbasic medium

It has been established that on heterocyclization of 3,5-dimethyl-2,6-diphenylpiperid-4-one oxime with acetylene in a superbasic medium migration of the 3a-CH3 group to the anionic nitrogen atom occurs, leading to the formation of 5,7-dimethyl-4,6-diphenyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine. The formation of the N-anion causes aromatization of the tetrahydropyridine ring. Tetrahydropyrrolo[1,2-c]pyrimidines are formed in the Trofimov reaction as a result of decomposition of the intermediate 3H-pyrrole in a retro-Mannich reaction.

Novel preparative method for synthesis of isoindolo[2,1-b]benz-2-azepine-8-carboxylic acids

Based on readily accessible homoallyl amines, we previously developed preparative methods for synthesis of substituted and spiro-annelated tetrahydroquinolines [1], 3-aza-11-oxatricyclo[6.2.1.01,6]undec-9enes (6,8a-epoxy isoquinolines) [2], γ-piperidoles [3], benz-2-azepines [4], isoindolo[2,1-a]quinoline-10carboxylic acids [5]. In continuing our work on studying the synthetic possibilities for furyl-substituted homoallyl amines, we carried out an original two-step synthesis for isoindolo[2,1-b]benz-2-azepine 3.

Study of the stereochemistry of N-H and N-vinyl-4,5,7-trimethyi-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines and their nitro derivatives by the method of 1H and 13C NMR

The configurations and conformational features of N-H and N-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines and their nitro derivatives were established by the method of 1H and 13C NMR spectroscopy. It was shown that the conformational uniformity of the piperideine ring in the compounds studied is strongly dependent on the character of the substituents in the pyrrole ring. A method for the determination of the orientation of the substituent at the α-position to the nitrogen atom of the piperideine ring, according to the direct 1JCH SSCC, was proposed.

Synthesis of hexahydro[1,4]diazocino[7,8,1-jk]carbazoles and 1-methoxy-9-(β-vinylethylamino)ethylcarbazoles

3-Ethylhexahydropyrazino[3,2,1-jk]carbazole is converted into hexahydro[1,4]diazocino[7,8,1-jk]carbazoles by the action of methyl propiolate and acetylacetylene in acetonitrile and into 1-methoxy9-(β-vinylethylamino)ethylcarbazoles by the action of acetylenedicarboxylic ester and methyl propiolate in methanol. 3-Benzyl-substituted pyrazinocarbazole does not react with alkynes.

Synthesis of Substituted and Condensed Tetrahydrospiro[benzo-2-azepinecyclohexanes] from 1-Cyano- and 1-Carbamoyl-5-methyl-4,5-dihydro-3H-spiro[benzo-2-azepine-3,1′-cyclohexanes]

Substitution of the nitrile group by hydroxylamine and hydrazine has been effected in 1-cyanodihydrospiro[benzo-2-azepine-3,1′-cyclohexane]. From the 1-cyano and 1-hydrazino derivatives tetrahydrospiro{1,2,3- and 1,2,4-triazolo[5,1-a]benzoazepine-5,1′-cyclohexanes} have been obtained. It was established that 1-carbamoyldihydrospiro[benzo-2-azepine-3,1′-cyclohexanes] are converted under the conditions of the Hoffmann reaction into spiro{diaziridino[3,1-a]benzo-2-azepine-3,1′-cyclohexane{, and is reduced by sodium borohydride to the tetrahydro derivative.

Amination of 4-Azafluorene under Chichibabin Reaction Conditions. Some Chemical Transformations of 1-Amino-4-azafluorene

Abstract4-Azafluorene is aminated by sodium amide in dimethylaniline at C(1). The oxidation of 1-amino-4-azafluorene was studied along with the condensation of this compound with acetic anhydride and its diazotization.

Synthesis and nitration of NH- and N-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines

It has been shown that the most efficient catalysts for the synthesis of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine from 1,2,5-trimethylpyridin-4-one and acetylene under Trofimov conditions are rubidium and potassium hydroxides. Use of Triton B or a mixture of trimethylbenzylammonium chloride with rubidium hydroxide as catalyst gives O-alkylated oxime. Their configurations and conformations were established through separation of the individual isomers of 1-vinyl-4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines. Acetyl nitrate nitration of the cis isomer of this compound gave the 2- and 3-nitro derivatives. Similar nitration of 4,5,7-trimethyl-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine gave the 2-nitro-7-hydroxy derivative.