6963-62-8

5292-53-5

6963-62-8

General procedure for the synthesis of ethyl 4-phenyl-1H-pyrazole-3-carboxylate from diethyl benzylidene malonate: in a 10 mL microwave glass vial, EtOH (1 mL) and pyrazolidine 6 (0.1 mmol) were added, followed by Cs2CO3 (16.5 mg, 0.05 mmol, 0.5 equiv). The reaction mixture was placed in a microwave reactor and radiated at 80°C for 10-15 min and the reaction progress was monitored by TLC. Upon completion of the reaction, EtOH was removed under vacuum. the residue was treated with 10 mL of water and the aqueous phase was extracted with EtOAc (2 × 10 mL). The organic phases were combined, dried with anhydrous Na2SO4, filtered and the filtrate was concentrated under vacuum. The residue was recrystallized by EtOAc/hexane (1:1) mixed solvent to give pure ethyl 4-phenyl-1H-pyrazole-3-carboxylate (compound 5) in quantitative yield.