Methyl chloroformate → HCID 131731842, compound

Participants

Reaction Conditions

Reaction Steps

An anhydrous tetrahydrofuran (THF) solution (20 ml) of crude 1-benzenesulfonyl-6-(tert-butyl-diphenyl-silanyloxymethyl)-1H-indole was cooled to −78° C., and a prepared tetrahydrofuran (THF) solution of lithium diisopropyl amide (LDA) was added thereto. This was stirred at −78° C. for 30 minutes. Methyl chloroformate (0.43 ml, 5.98 mmol) was added thereto, and this was stirred at −78° C. for 30 minutes. An aqueous solution saturated with ammonium chloride was added to the reaction mixture, and this was warmed to room temperature. After ethyl acetate extraction, the organic layer was dried over anhydrous sodium sulfate. The desiccant was removed by filtration and concentration was performed. Then, the residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (hexane/ethyl acetate=98/2 to 4/1). Thus, 1-benzenesulfonyl-6-(tert-butyl-diphenyl-silanyloxymethyl)-1H-indole-2-carboxylic acid methyl ester was obtained as a brown amorphous material (882 mg, 51%).

Provenance & Evidence