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Scientific Publications of Jos Aerts

5_Imino-delta3-1,2,4-Thiadiazoline Derivatives with a Linear N-S...O Grouping. Synthesis and Crystal Structures

G.L'abb, G.Vermeulen, S.Toppet, G.S.D.King, J.Aerts and L.Sengier

J.Heterocycl.Chem., 18, 1309-1317 (1981)


A series of carbonyl derivatives of 5-imino-delta3-1,2,4-thiadiazolines has been prepared and shown by X-ray analysis of a selected sample to have a trithiapentalene-like structure. When diphenylketene was used as acylating reagent, the primary product (14), obtained at room temperature, rearranged on heating in a polar solvent into delta2-thiazolin-4-one (15). The structure of 15 has been confirmed by X-ray analysis, and shown to be a zwitterion. Rearranged products (i.e., 16 and 20-22) were also obtained when 3 was reacted with dimethyl acetylenedicarboxylate or methanesulfonyl chloride, wehereas tosyl chloride gave normal tosylated derivatives (17-19). The latter have also a nearly linear N-S...O arrangement, but the interaction between S and O is weak.