N. A. Klyuev

Quaternary salts of quinolybenzimidazoles

The nitrogen atoms of the benzimidazole ring are alkylated initially in the quaternization of 2-(2-quinolyl)benzimidazole, and the nitrogen atom of the quinoline ring is alkylated only after this. Pyridyl- and quinolylbenzimidazoles and their quaternary salts were synthesized in order to study geometrical isomerism in the dihetaryl series. It was concluded that geometrical isomerism cannot occur in the case of the protonated forms or any other quaternary salts of dihetaryls, since as a result of the mutual electron-acceptor effect of the heteroaromatic cations the carbon-carbon bond between them is converted to a single σ bond, despite the fact that it is a bond between two sp2 carbon atoms.

Benzoxazole in the hetarylation reaction

N-Acylbenzoxazolium salts formed in situ in the reaction of benzoxazole with acylating agents react with indoles with opening of the oxazole ring to give tri(3-indolyl)methanes. Hetarylation products are formed in the reaction of N-acylbenzoxazolium salts in situ with oxindole and pyrazolone.

Reactions of cyclammonium cations

The reaction of 1,2-diaminopyridinium salts with α-dicarbonyl compounds or α-halogeno ketones forms pyrido[1,2-b][1,2,4]triazinium salts. A methyl group present in position 2 of one of these salts condenses with aldehydes, giving styryl derivatives and reacts with orthoesters to give cyanines.

Transformations of the sulfur analogs of Β-carbolins under the influence of nucleophiles

The reaction of the quaternary salts of some thienopyridines (the sulfur analogs of Β-carbolins) with nucleophilic reagents was investigated. It was shown that either the methylene anhydro bases are formed or one or both heterocyclic rings are transformed, depending on the structure of the thienopyridine and on the reaction conditions.

TRANSFORMATIONS OF SOME ALKALOIDS OF THE CARBOLINE SERIES UNDER THE INFLUENCE OF ALKALI

The reaction of quaternized forms of two alkaloids of the β-carboline series — harman and brevicarine — with alkali was investigated. It was established that, under the reaction conditions, the harman derivative undergoes recyclization of the pyridine part of the molecule, whereas in the analogous brevicarine derivative the pyridine ring does not undergo transformations.

Hetarylation of indolizines

The direct incorporation of quinoline, isoquinoline, acridine, imidazole, and benzimidazole residues in the indolizine ring was accomplished by reaction of N-heteroaromatic compounds with indolizine derivatives in the presence of acylating agents.

Perimidine in the hetarylation reaction

Indoles and pyrroles were hetarylated by perimidines in the presence of benzoyl chloride. N-Acyl derivatives of 2-indolyl(pyrrolyl)-2, 3-dihydroperimidine were synthesized.