Intramolecular redox cyclization upon oxidation of a sulfur(II)-containing diazene: X-ray structures of (Ar=4-CH3C6H4) and MeSO2N(4-CH3C6H4)CN=NC(C6H4CH3-4)NSO2Me

The reaction of Z,E,Z-PhSN=C(Ar)N=NC(Ar)=NSPh (Ar = 4-CH 3 C 6 H 4 ) (1a) with MCPBA results in ring closure via an intramolecular redox process to give the 1,2,3,5-thiatriazole [Formula: see text] (4). An X-ray structural determination revealed that 4 contains a planar five-membered CNS(VI)NN ring with d(N—N) = 1.402(6) Å. The reaction of ArCN 2 (SiMe 3 ) 3 (Ar = 4-CH 3 C 6 H 4 ) with one equivalent of MeSO 2 Cl, followed by two equivalents of PhSeCl, produces the sulfonyl-containing diazene MeSO 2 N=C(Ar)N=N(Ar)C=NSO 2 Me (11), which was shown by X-ray crystallography to adopt a Z,E,Z geometry. By contrast, the reaction of ArCN 2 (SiMe 3 ) 3 with one equivalent of ArS(O)Cl, followed by two equivalents of PhSeCl, yielded the sulfur(II)-containing diazene Z,E,Z-ArSN=C(Ar)N=NC(Ar)=NSAr (Ar = 4-CH 3 C 6 H 4 ) (1b). Keywords: thiatriazoles, sulfonyl diazenes, intramolecular redox cyclization.