Ethyl 5-methyl-1H-pyrazole-3-carboxylate → ethyl 4-iodo-5-methyl-1H-pyrazole-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of ethyl 5-methyl-1H-pyrazole-3-carboxylate (2 g, 12.97 mmol, 1.00 equiv) in N,N-dimethylformamide (50 mL) was added NIS (3.5 g, 15.56 mmol, 1.20 equiv) in portions. The reaction mixture was stirred at 25° C. for 4 h and then diluted with 30 mL of H2O. The resulting mixture was extracted with 2×30 mL of ethyl acetate. The combined organic layers were washed with 2×50 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with 0-50% of ethyl acetate in petroleum ether to give 3.6 g (99%) of ethyl 4-iodo-5-methyl-1H-pyrazole-3-carboxylate as a white solid. LCMS (method D, ESI): RT=1.27 min, m/z=281.0 [M+H]+.

Provenance & Evidence