反应详情

A solution of 6.5 g of (S)-2-[(5-Hydroxy-1-phenyl-1H-pyrazole-3-carbonyl)-amino]-pentanedioic acid 5-tert-butyl ester 1-methyl ester in 175 ml of DMF was cooled to 0° C. Then, 644 mg of sodium hydride (60% in mineral oil) was added portionwise over 20 min. Further 20 min after completion of the addition 2.9 g of 1-Bromo-3,3-dimethyl-butan-2-one was added and the reaction mixture was allowed to warm to RT. After striring for 16 h the reaction mixture was diluted with brine and extracted with DCM. The organic phase was dried over MgSO4 and the solvents were removed under reduced pressure. The crude product was purified by chromatography on silica gel eluting with a gradient of n-heptane/ethyl acetate. The fractions containing the product were combined and the solvent evaporated under reduced pressure. Yield: 3.3 g.

1. additionwas added
2. extractionextracted with DCM
3. dry with materialThe organic phase was dried over MgSO4
4. customthe solvents were removed under reduced pressure
5. customThe crude product was purified by chromatography on silica gel eluting with a gradient of n-heptane/ethyl acetate
6. additionThe fractions containing the product
7. customthe solvent evaporated under reduced pressure