反应详情

A mixture of 5-tert-butyl-4-chloro-2-methyl-2H-pyrazole-3-carboxylic acid ethyl ester (prepared as described in the previous step, 2.20 g, 9.00 mmol) and 3 N aqueous NaOH (7.50 mL, 22.5 mmol) in MeOH (40 mL) was stirred at room temperature for 4 h. The solvent was removed under reduced pressure, and the residue was treated with H2O (30 mL) and washed with Et2O. The aqueous layer was then acidified to pH 7 by 2 N aqueous HCl and extracted with DCM. The combined organic layers were washed with brine and dried with Na2SO4. The solvent was removed in vacuo to yield the title compound as a white solid. 1H-NMR (400 MHz, CDCl3) δ: 10.41 (br s, 1H), 4.12 (s, 3H), 1.42 (s, 9H). Mass Spectrum (LCMS, ESI pos.) Calculated for C9H13ClN2O2: 217.1 (M+H), Measured: 217.1.

1. customprepared
2. customThe solvent was removed under reduced pressure
3. additionthe residue was treated with H2O (30 mL)
4. washwashed with Et2O
5. extractionextracted with DCM
6. washThe combined organic layers were washed with brine
7. dry with materialdried with Na2SO4
8. customThe solvent was removed in vacuo