Hydrochloric Acid → 1-benzyl-5-methyl-1H-pyrazole-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 1-benzyl-5-methyl-1H-pyrazole-4-carboxylate (200 mg, 0.86 mmol), lithium hydroxide monohydrate (111 mg, 2.62 mmol), tetrahydrofuran (10 mL), methanol (2 mL) and water (2 mL) was stirred at 20° C. for 4 hours. The mixture was acidified to pH=1 with concentrated hydrochloric acid and then extracted with ethyl acetate (15 mL×3). The combined organic phase was dried by sodium sulfate, and then filtered. The filtrate was concentrated in vacuo and separated by chiral HPLC (condition: column AD-H (20 mm*250 mm*5 μm), hexane: ethanol (0.2% DEA)=50:50, flow rate: 13 mL/min) to give 1-benzyl-5-methyl-1H-pyrazole-4-carboxylic acid (75 mg, 40%). LRMS (M+H+) m/z: calcd. 216.09. found 216.

Provenance & Evidence