Benzyl Alcohol → benzyl (2-{6,6-dimethyl-1-[2-(trimethylsilyl)ethoxymethyl]-4,5,6,7-tetrahydro-1H-indazol-3-yl}-1-[2-(trimethylsilyl)ethoxymethyl]-1H-indol-6-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere, to a solution of 2-{6,6-dimethyl-1-[2-(trimethylsilyl)ethoxymethyl]-4,5,6,7-tetrahydro-1H-indazol-3-yl}-1-[2-(trimethylsilyl)ethoxymethyl]-1H-indole-6-carboxylic acid (26 g, 45 mmol), triethylamine (8.2 ml, 59 mmol) and benzyl alcohol (18 ml, 180 mmol) in toluene (260 ml) was added dropwise diphenylphosphoryl azide (12 ml, 54 mmol) at 115° C. over 2 hr. After cooling, water was added to the reaction mixture, and the organic layer was separated. Then, the organic layer was washed successively with water and saturated brine, and dried over magnesium sulfate. Magnesium sulfate was removed by filtration, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel chromatography, and slurry-washed in hexane (210 ml) with heating at 60° C. The resulting crystals were collected by filtration, washed with hexane, and dried under reduced pressure to give the title compound (28 g, yield 91%).

Provenance & Evidence