Reaction of p-tolualdehyde hydrazone with disulfur dichloride in the presence of DBU gave 2,5-di (p-tolyl)-1,3,4-thiadiazole (1a) in 54% yield. Phenyldiazomethane also reacted with disulfur dichloride to afford 2,5-diphenyl-1,3,4-thiadiazole (1b) in 80% yield.

Thiazole derivatives R 0260Synthesis of 1,3,4-Thiadiazoles from Aldehyde Hydrazones. -1,3,4-Thiadiazoles (II) are formed together with arylazines (III) when arylaldehyde hydrazones (I) are reacted with S2Cl2. The reaction is assumed to proceed via the corresponding thiones and diazoalkanes formed as intermediates. -(OKUMA*, K.; NAGAKURA, K.; NAKAJIMA, Y.; KUBO, K.; SHIOJI, K.; Synthesis 2004Synthesis , 12, 1929Synthesis -1931 Dep. Chem., Fac. Sci., Fukuoka Univ., Jonan, Fukuoka 814-01, Japan; Eng.) -M. Bohle 01-109