Facile synthesis of fluorine‐containing [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone, 2‐amino‐4‐aryl‐5‐arylazothiazoles and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles through N ‐aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromide

N ‐Aryl‐α‐oxo‐α‐arylethanehydrazonoyl bromides 2 react with potassium thiocyanate in ethanol leading to the formation of [4‐aryl‐4,5‐dihydro‐5‐imino‐1,3,4‐thiadiazol‐2‐ylaryl]methanone 5 in quantitative yield. Treatment of 2 with thiourea and β‐diketones affords 2‐amino‐4‐aryl‐5‐arylazothiazoles 4 and 3‐aroyl‐4‐acetyl/benzoyl‐5‐methyl‐1‐phenylpyrazoles 6 in 65–70 and 60–70% yields respectively. Compound 5 has also been subjected to acetylation and chloroacetylation. All the compounds are characterized by their analytical and spectral (ir, 1 H‐nmr and ms) data. Mass fragmentation patterns of these compounds are discussed.