Methyl chloroformate → HCID 58428014, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of carbonic acid ethyl ester 1-hydroxy-8-methoxy-2-oxo-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-4-yl ester (preparation example 13, step 1; compound P1ii.11) (140 mg, 0.33 mmol), triethylamine (93 μl, 68 mg, 0.67 mmol) and 4-dimethylaminopyridine (2 mg) in tetrahydrofuran (3 ml) at 0° C. was added a solution of methyl chloroformate (33 μl, 41 mg, 0.43 mmol) in tetrahydrofuran (2 ml) dropwise. The suspension was stirred at 0° C. for one hour, and at room temperature for one hour. The reaction mixture was evaporated, diluted with ethyl acetate and filtered to remove salts. The filtrate was washed with a saturated aqueous sodium hydrogen carbonate solution (2×15 ml) and brine, dried over sodium sulfate and concentrated. The oily residue was purified by chromatography on silica gel (ethyl acetate/hexane 1:2). Yield: 30 mg of carbonic acid ethyl ester 8-methoxy-1-methoxycarbonyloxy-2-oxo-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-4-yl ester (title compound P1ii.13) as a colorless gum.

Provenance & Evidence