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Starting from the 3‐acetyl derivative (I), compounds (IV) and (VI) are prepared on one hand, and via the 3‐bromoacetyl derivative (VIIIa) compounds (VIIIb), (IX) as well as (X) and (XIII) are obtained on the other.

Coupling of the β‐oxothioanilide (I) with the aryldiazonium salts (II) leads to the formation of the arylhydrazones (III) which are cyclized with semicarbazide hydrochloride (IV) to form the pyrazoles (V).