Acetic Acid → 1-Benzyl-5-oxo-1,4,5,6-tetrahydro-cyclopentapyrazole-3-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a solution of the intermediate from step A (2.15 g, 8.45 mmol) in ethanol (100 mL) was added benzyl hydrazine hydrochloride (1.8 g, 9.22 mmol) and HOAc (10 mL). The reaction mixture was stirred at room temperature for 16 hours and then refluxed at 70° C. for 30 minutes. The reaction was cooled to room temperature and concentrated in vacuo. The residue was dissolved in ethyl acetate and washed with water, saturated NaHCO3, and brine. The organic layer was dried over anhydrous Na2SO4 filtered and concentrated in vacuo. The residue was purified by flash chromatography (SiO2) using 30% ethyl acetate-hexanes to give the desired product (1.64 g) a brown oil.

Provenance & Evidence