反应详情

To a solution of 3-(5-bromo-3-fluoro-2-methyl-phenyl)-4-hydroxy-8-methoxy-1,8-diaza-spiro[4.5]dec-3-en-2-one (350 mg) and ethyl chloroformate (77 μl) in acetonitrile (2 ml) was added pyridine (80 μA) and the reaction mixture stirred at room temperature for one hour. The mixture was poured on diluted HCl and extracted with ethyl acetate (3×). The combined organic layers were washed with brine, dried over sodium sulfate and concentrated. The residue was purified by chromatography on silica gel (ethyl acetate/cyclohexane 3:1). Yield: 310 mg of carbonic acid 3-(5-bromo-3-fluoro-2-methyl-phenyl)-8-methoxy-2-oxo-1,8-diaza-spiro[4.5]dec-3-en-4-yl ester ethyl ester (title compound E4) as a solid.

1. extractionextracted with ethyl acetate (3×)
2. washThe combined organic layers were washed with brine
3. dry with materialdried over sodium sulfate
4. concentrationconcentrated
5. customThe residue was purified by chromatography on silica gel (ethyl acetate/cyclohexane 3:1)