反应详情

To a solution of 2-(4-acetyl-5-methyl-1H-pyrazol-1-yl)acetic acid (1.17 g, 6.42 mmol, as a mixture of regioisomers from the previous step) in MeOH (8.8 ml)-Toluene (30.6 ml) was added a 2 M solution of (trimethylsilyl)diazomethane in ether (4.8 ml, 9.6 mmol) dropwise at 0° C. The resulting solution was allowed to warm to rt and stirred for 120 min. The reaction was quenched by addition of AcOH (3 ml) and the solvent was concentrated in vacuo. The crude product was purified by silica gel column chromatography (CH2Cl2:MeOH=30:1) to give the desired product along with a mixture of regioisomers (>99% yield). 1H NMR (270 MHz, CDCl3) δ 2.45 (3H, s), 2.53 (3H, s), 3.79 (3H, s), 4.90 (2H, s), 7.88 (1H, s).

1. customThe reaction was quenched by addition of AcOH (3 ml)
2. concentrationthe solvent was concentrated in vacuo
3. customThe crude product was purified by silica gel column chromatography (CH2Cl2:MeOH=30:1)