Search for New Precursors of 2,5-Diiminothiazolidines

2-Iminothiazolidine-4,5-diones are prone to isomerization during the reaction of 1,3-dipolar cycloaddition with nitrile imines and aza-Wittig reactions, but the introduction of a polymethylene bridge between the nitrogen atoms fixes the structure of the starting heterocycle. In this work, the possibilities of various fragments using to fix the structure of 2-iminothiazolidines and their further aza-Wittig reactions to obtain diimines containing both endocyclic and exocyclic C=N bonds were investigated. It was shown that various 2-iminothiazoline-4,5-dione can be synthesized, depending on the reaction of oxalyl chloride and cyclic thiourea derivatives conditions, and these derivatives form the same diimines during the aza-Wittig reactions.