The structure of the diazonium coupling products of phenacyl thiocyanate and phenacyl selenocyanate with diazotized 3‐phenyl‐5‐aminopyrazole

The reaction of diazotized 3‐phenyl‐5‐aminopyrazole with phenacyl thiocyanate 1a and phenacyl selenocyanate 1b afforded directly 2‐imino‐3‐(3‐phenyl‐5‐pyrazolyl)‐5‐benzoyl‐2,3‐dihydro‐1,3,4‐thiadiazole monohydrate 9a and 2‐imino‐3‐(3‐phenyl‐5‐pyrazolyl)‐5‐benzoyl‐2,3‐dihydro‐1,3,4‐selenadiazole monohydrate 9b , respectively. The products 9a and 9b were also obtained from the reaction of C ‐benzoyl‐ N ‐(3‐phenyl‐5‐pyrazolyl)formohydrazidoyl bromide 10 with potassium thiocyanate and potassium selenocyanate, respectively. Acetylation, benzoylation, and nitrosation of 9 afforded the corresponding diacetyl, dibenzoyl, and nitroso derivatives 11‐13 , respectively. Cyclization of C ‐benzoyl‐ N ‐(3‐phenyl‐5‐pyrazolyl)‐nitrilimine 6 was shown to give the pyrazolo [5,1‐ d ]triazole 8 and not the pyrazolo[5,1‐ c ]‐ as ‐triazine derivative 7 , as previously reported.