Studies on the structure of some derivatives of 1,3-thiazolidine-2-thione and Δ2-1,3-thiazoline-2-thiol
Two types of reactions have been observed for the ambident anion of 1,3-thiazolidine-2-thione: regioselective N-acylation and S-alkylation. The structures of the products, amides and thioethers, were determined by X-ray crystallographic analysis and by assignment of the 13C n.m.r. chemical shifts. The regioselectivity of the reactions is rationalised in terms of the hard–soft acid-base principle and has been exemplified by model experiments.