反应详情

A mixture of benzyl 3-methyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (74 g, 285 mmol), Pd/C (45 g, 10% on C) and EtOAc (1 L) was treated in a Parr apparatus at room temperature with H2 (15 psi) for 5 hours. The catalyst was filtered off over Celite and the solvent was removed in vacuo. Et2O (1 L) and water (200 mL) were added and the aqueous layer was made slightly basic (pH 8-9) with Na2CO3. The layers were separated and the aqueous layer was extracted with Et2O (5×200 mL). To the aqueous layer was added dropwise conc. HCl until pH 4-5 and followed by extraction with Et2O (3×500 mL). The combined organic layers were dried (MgSO4), filtered, evaporated in vacuo to give the title compound in 74% yield 7.4 g; m.p. 308-310° C. (dec.) m/z 195 [M+H]+

1. additionwas treated in a Parr apparatus at room temperature with H2 (15 psi) for 5 hours
2. filtrationThe catalyst was filtered off over Celite
3. customthe solvent was removed in vacuo
4. additionEt2O (1 L) and water (200 mL) were added
5. customThe layers were separated
6. extractionthe aqueous layer was extracted with Et2O (5×200 mL)
7. additionTo the aqueous layer was added dropwise conc. HCl until pH 4-5
8. extractionfollowed by extraction with Et2O (3×500 mL)
9. dry with materialThe combined organic layers were dried (MgSO4)
10. filtrationfiltered
11. customevaporated in vacuo