Hydrochloric Acid → 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

Participants

Reaction Steps

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.

Provenance & Evidence