反应详情

温度

70 °C

A mixture of 2-(4-bromo-2-fluorobenzyl)-1,3-dioxo-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine-4-carboxylic acid (-)-menthyl ester (67.0 g), anhydrous potassium carbonate (36.0 g) and tert-butyl bromoacetate (33.0 g) in anhydrous dimethylformamide (200 ml) was stirred under the stream of nitrogen at 70° C. for 2.5 hours. After removal of the insoluble materials by filtration, the filtrate was poured into water and extracted with ethyl acetate. The extracts were washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and evaporated under reduced pressure. The residue was recrystallized from n-hexane to give the title compound (Diastereomer A) (23.5 g, 28.8%) as colorless crystals, mp 99°-100° C.

1. customAfter removal of the insoluble materials
2. filtrationby filtration
3. additionthe filtrate was poured into water
4. extractionextracted with ethyl acetate
5. washThe extracts were washed with saturated aqueous sodium chloride solution
6. dry with materialdried over anhydrous sodium sulfate
7. customevaporated under reduced pressure
8. customThe residue was recrystallized from n-hexane