The reaction of 5-(arylamino)-l, 2, 3, 4thiatriazol8s 1 with isocyanates initially gives 1, 2, 3, 4thiatriazol-5-ylureae 3 which can be isolated when the aryl group has b-dkyl substituents. Compounds 3 rearrange to 21 in the presence of triethylamine and then react with the second equivalent of isocyanate to give (4-aryl-2-alky1-3-oxo-1, 2, 4-thiadiazolidin-5- ylidene) urw 12 rather than the (3-oxo-A4-1, 2, 4thiadiezolin-5yl) ureas 7 which had been ...
