Novel heterocycles: 1,3,4-oxadithiolane, 1,3,4-oxadiselenolane, 1,3-oxathietane and 1,3-oxaselenetane derivatives

Abstract

The reaction of the monohydrazone 1 of 2,2,4,4-tetramethyl-1,5-diphenylpentane-1,5-dione with S2Cl2 affords a bicyclic 1,3,4-oxadithiolane derivative 2, which gives an equilibrium mixture of a 1,3-oxathietane 7 and its ring-opened isomer 6 on treatment with P(NMe2)3, whilst the 1,3,4-oxadiselenolane 3 prepared from 1 and Se2Cl2 affords a 1,3-oxaselenetane 8 and a cyclic ketone 9 on treatment with the same reagent.