Methyl iodide → (1R,7S)-4-(2,5-dichlorophenyl)-1,3,10,10-tetramethyl-3,4-diazatricyclo[5.2.1.02,6]dec-2(6)-en-5-one

Participants

Reaction Conditions

Reaction Steps

A mixture of (4S,7R)-2-(2,5-dichloro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (Intermediate 44; 12.55 g, 37.2 mmol) and iodomethane (12 mL, 193 mmol) in dimethylformamide (75 mL) was heated at 100° C. for 3 h and then cooled to room temperature. The solvent was evaporated, dichloromethane (300 mL) was added and the solution was washed with saturated aqueous sodium thiosulfate (100 mL), water (2×100 mL), and brine (100 mL). The solution was dried (magnesium sulfate), filtered, evaporated, and purified by flash column chromatography, eluting with 50-100% ethyl acetate/petroleum ether. Fractions homogeneous for the product were evaporated and ethyl acetate (100 mL) was added. The mixture was stirred at room temperature for 10 min and then hexane (300 mL) was added. The mixture was stirred at room temperature for 10 min and then cooled to 0° C. and filtered. The filter cake was washed with hexane and dried. The solid was dissolved in ethanol (100 mL) and treated with activated charcoal (0.8 g). The mixture was stirred at room temperature for 30 min, filtered through celite, and then evaporated. The residue was dried at 70° C. overnight to give (4S,7R)-2-(2,5-dichloro-phenyl)-1,7,8,8-tetramethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (9.18 g, 70%) as a white solid. ES(+)-MS (M+H) 351.

Provenance & Evidence