反应详情

To a solution of ethyl 2-methyl-2-(4-nitro-1H-pyrazol-1-yl)propanoate (45 g) obtained in Step F of Example 103 in tetrahydrofuran (400 mL) was added gradually dropwise diisopropylaluminium hydride in toluene (1.5 M in toluene, 400 mL) while maintaining the internal temperature of −20° C. or less, and the reaction mixture was stirred overnight while it was allowed to be warmed. To the reaction mixture was added aqueous potassium sodium tartrate solution in an ice bath, and the mixture was extracted with ethyl acetate. The obtained organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate) to give the crude title compound (36 g).

1. temperaturewhile maintaining the internal temperature of −20° C. or less
2. temperatureto be warmed
3. extractionthe mixture was extracted with ethyl acetate
4. washThe obtained organic layer was washed with saturated brine
5. dry with materialdried over anhydrous magnesium sulfate
6. customthe solvent was evaporated under reduced pressure
7. customThe residue was purified by silica gel column chromatography (ethyl acetate)