StarchSulfuric Acid (SSA) as Catalyst for a One‐Pot Synthesis of 1,5‐Diaryl‐1 H ‐pyrazoles

Protocols with starchsulfuric acid (SSA) as reusable catalyst for the synthesis of aryl‐1 H ‐pyrazoles are described. SSA acted as an efficient and environmentally friendly catalyst for the regioselective condensation of BaylisHillman adducts 1 with phenylhydrazine hydrochloride leading to the new 1,5‐diaryl‐1 H ‐pyrazole 2a – 2e in excellent yields ( Scheme and Table 1 ).