Synthesis and Fungitoxicity of 1,2,4-Triazolo [3,2-b][1,3,4]-thiadiazole-6-thiones

Several 2.5-diaryl (or unsubstiuted)-1, 2, 4-triazolo [3, 2-b] [1, 3, 4]-thiadiazole-6-thiones (III a-f) and 2-aryl-6-arylimino-1,2,4-thiadiazolo [3,2-b]-1,3,4-thiadazoles (IV a-f) have been synthesized by oxidation and cyclization of corresponding N¹-aryl-N³- (5-aryl-1, 3, 4-thiadiazole-2-yl) thioureas (IIa-f) with SOCl₂ pyridine and I₂/EtOH respectively. The required thioureas (II a-f) were prepared by reacting 2-amino-1, 3, 4-thiadiazoles (I a-c) either by mixture of NH₄ SCN and Ar’ COCl or Ar’-N=C=S. Twelve such compounds have been synthesized and screened for fungitoxity in vitro against Aspergillus niger and Fusarium oxysporium.