反应详情

温度

-78 °C

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%).

1. stirringthis was stirred at −78° C. for 30 minutes
2. temperaturethis was warmed to room temperature
3. extractionAfter ethyl acetate extraction
4. dry with materialthe organic layer was dried over anhydrous sodium sulfate
5. customThe desiccant was removed by filtration and concentration
6. customThen, the residue obtained by concentration under reduced pressure
7. customwas purified by silica gel column chromatography (hexane/ethyl acetate=98/2 to 4/1)