Diisopropylamine → ethyl 3-(cyclopropanecarbonyl)-1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

According to Scheme 16: Butyl lithium 2.5 M (9.9 mmol, 4 mL) was added to a solution of diisopropylamine (9.9 mmol, 1.4 mL) in THF (20 mL) at −78° C. and the reaction mixture was stirred at −78° C. for 5 minutes and then at room temperature. To the resulting LDA solution was added at −78° C. a solution of ethyl 1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate (7.61 mmol, 1.98 g) in THF (30 mL) and the reaction mixture was stirred for 15 minutes at −78° C. Then N-methoxy-N-methylcyclopropanecarboxamide (9.14 mmol, 1.18 g) in THF (10 mL) was added and the reaction mixture was stirred at room temperature. The reaction mixture was diluted with AcOEt and washed with a saturated aqueous solution of NH4Cl. The combined organic phases were dried over MgSO4, were filtered and solvents were evaporated. The crude mixture was purified by flash chromatography over silica gel using cyclohexane/AcOEt (90:10) as eluent to yield ethyl 3-(cyclopropanecarbonyl)-1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate (0.74 mmol, 244 mg, 9%).

Provenance & Evidence