Kovalenko N. 1,3-Dibromoacetone and other a-haloketones in the synthesis of indolizines and condensed imidazoles by the Chichibabin reaction

The dissertation is devoted to investigation of expansion of the Chichibabin type II reaction application limits and its proceeding for the mechanism investigation.Two components take part in the Chichibabin type II reaction: pyridine and a-haloketone; both of them were varied. In the case of 1,3-dibromoacetone as a-haloketone, N-bromo-w-bromoacetonyl-a-picolinium bromide was obtained, which appeared to be an alkylating agent for thioles.Intermediates of the reaction of 1,3-dibromoacetone with 2-aminopyridines, 2-aminopyrimidines and 2-aminothiazoles, namely, salts with a carbinolamine structure were isolated. Different intermediates were obtained in the case of 2-aminoazines and 2-aminothiazoles. These novel intermediates also appeared to be alkylating agents.The reactions of oxidative bromination of imidazo[1,2-a]pyridines hydrobromides with hydrogen peroxide were performed at first time. Synthetic possibilities of imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines and imidazo[2,1 b][1,3]thiazoles were investigated.