REGIOSELECTIVE ADDITION OF 5-AMINO-3-BENZYLTHIO-1,2,4-TRIAZOLE AND ITS ANALOGS WITH ARYLISOCYANATES

The orientation of the addition of 5-amino-3-benzylthio-1,2,4-triazole and its analogues (pyrazole) (1) with the aryl isocyanate can be dire cted by controlling the reaction temperature and one of the product, n o-1-arylaminocarponyl-3-benzylthio-1,2,4-triazole (pyrazole) (2), can rearrange at 170 degrees C to another product, 5-arylureylene-3-benzyl thio-1,2,4-triazole, (pyrazole) (3). A plausible mechanism explanation for this rearrangement reaction was presented. It was suggested that the rearrangement reaction could be referred to the thermodynamics tra nsposition leading to the predominant 5-arylureylene-3-beneylthio-1,2, 4-triazole energy preferentially.