1,4-Dichalcogenins: Synthesis from Dichloroethenes and Elemental Chalcogens in a Hydrazine Hydrate–Potassium Hydroxide System

A possibility of the synthesis of 1,4-dichalcogenins by the reaction of vinylidene chloride or 1,2-dichloroethene with elemental chalcogenes in a hydrazine hydrate–KOH system was studied. When vinylidene chloride was used, the maximum yield of 1,4-diselenin was 38%; 1,4-ditellurine was not formed. Diselenin was obtained from 1,2-dichloroethene in 45% yield, while ditellurine was prepared in 21% yield. A plausible mechanism for the formation of dichalcogenin molecules was proposed, which makes it possible to explain the differences in the behavior of 1,1- and 1,2-dichloroethenes in the reaction with potassium telluride. When two chalcogenes were introduced into the reaction, 1,4-dichalcogenins with different chalcogen atoms were obtained with yields of up to 7%.