Cyanoethylation of 2,5-dimethyltetrahydro-4-thiopyranone isomers and selective reduction of 2,5-dimethyl-5-(β-cyanoethyl)tetrahydro-4-thiopyranone and — 4-pi pe ridone

It has been found that only the cis isomer (liquid) of 2,5-dimethyltetrahydro-4-thiopyranone is cyanoethylated under the usual conditions. 2,5-Dimethyl-5-(-carboxyethyl)tetrahydro-4-thiopyranone was synthesized by the acid hydrolysis of 2,5-dimethyl-5-(-cyanoethyl)-tetrahydro-4-thiopyranone. The selective reduction with aluminum isopropoxide of 2,5-dimethyl-5-(-eyanoethyl) tetrahydro-4-thiopyranone and of the individual isomers of 2,5-dimethyl-5-(-cyanoethyl)-4-piperidone gave the isomeric 2,5-dimethyl-5-(-cyanoethyl)-tetrahydro-4-thiopyranols and -4-piperidols. The reaction of the isomeric 5-cyanoethyl-4-piperidols with allyl bromide gave the corresponding 1-allyl-2,5-dimethyl-5(-cyanoethyl)-4-piperidols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 12–14, January, 1972.