Trimethylsilyldiazomethane → 2-(3-Methoxycarbonyl-phenyl)-4-oxo-1,3,8-triaza-spiro[4.5]dec-1-ene-8-carboxylic acid tert-butyl ester

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Reaction Steps

(Trimethylsilyl)diazomethane (2.0 M in hexane, 4.0 ml, 8.0 mmol) was added dropwise to a solution of 2-(3-carboxy-phenyl)-4-oxo-1,3,8-triaza-spiro[4.5]dec-1-ene-8-carboxylic acid tert-butyl ester (200 mg, 0.54 mmol) in methanol (10 ml). The mixture was stirred at room temperature for one hour, and (trimethylsilyl)diazomethane (1.0 ml, 2.0 mmol) was then further added, followed by stirring for one hour. The reaction mixture was concentrated under reduced pressure, and the resulting solid was then washed with a solution of hexane/ethyl acetate=5/1 to give 2-(3-methoxycarbonyl-phenyl)-4-oxo-1,3,8-triaza-spiro[4.5]dec-1-ene-8-carboxylic acid tert-butyl ester (91.5 mg, 44%).

Provenance & Evidence