反应详情

To a solution of 1-isopropyl-1h-pyrazole-3-carboxylic acid (0.9757 g, 6.33 mmol, Matrix Scientific) in MeOH (31.6 ml) in a glass pressure vessel was added sulfuric acid (0.355 ml, 6.33 mmol Sigma Aldrich). The vessel was sealed and the r×n was brought to reflux to stir. (NOTE: A portable blast shield was used.) R×n was allowed to stir for 5 hours. The r×n was concentrated in vacuo. The residue was diluted with water and extracted with EtOAc. The organic extract was washed with water, dried over MgSO4, filtered and concentrated in vacuo to give methyl 1-isopropyl-1H-pyrazole-3-carboxylate (0.8073 g, 4.80 mmol, 76% yield) as a clear oil. MS m/z=168.9 [M+H]+. Calculated for C8H12N2O2: 168.09. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.55 (d, J=6.85 Hz, 6 H) 3.93 (s, 3 H) 4.63 (dt, J=13.50, 6.75 Hz, 1 H) 6.83 (d, J=2.35 Hz, 1 H) 7.46 (d, J=2.35 Hz, 1 H)

1. customThe vessel was sealed
2. temperatureto reflux to stir
3. concentrationThe r×n was concentrated in vacuo
4. additionThe residue was diluted with water
5. extractionextracted with EtOAc
6. extractionThe organic extract
7. washwas washed with water
8. dry with materialdried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated in vacuo