反应详情

To a mixture containing methyl 3-acetyl-4-chloro-1H-pyrazole-5-carboxylate (1.3 g, 0.0064 mol) in THF (30 ml), lithium hydroxide (1.35 g, 0.032 mol) in water (15 ml) was added dropwise at 5-10° C. The reaction mixture was stirred at RT for 18 h. Cold water (15 ml) was added and the pH was adjusted to ˜4 with 1N potassium bisulfate. The product was extracted with ethyl acetate, the organic layer dried with anhydrous Na2SO4 and concentrated. The crude product was purified by recrystallization from diethyl ether/n-hexane. Yield 56%. 1H-NMR (400 MHz; DMSO-d6): δ 2.57 (s, 3H), 13.91 (bs, 1H), 14.69 (s, 1H).

1. additionwas added dropwise at 5-10° C
2. extractionThe product was extracted with ethyl acetate
3. dry with materialthe organic layer dried with anhydrous Na2SO4
4. concentrationconcentrated
5. customThe crude product was purified by recrystallization from diethyl ether/n-hexane