Hydrochloric Acid → HCID 57941422, compound

Participants

Reaction Conditions

Reaction Steps

Triethylamine (1.7 mL, 12.2 mmol) was added dropwise to a cooled (0° C.) solution of (1R,4R)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl chloride (Intermediate 20; 1.25 g, 5.82 mmol) in 1,2-dichloroethane (10 mL) over 1 min. A solution of N′-biphenyl-2-yl-N-methyl-hydrazinecarboxylic acid tert-butyl ester (1.09 g, 3.65 mmol) in 1,2-dichloroethane (15 mL) was added over 2 min. The reaction mixture was stirred at 0° C. for 15 min, at room temperature for 15 min, and then in an oil bath at 50° C. for 1 h. The reaction mixture was cooled. A solution of HCl in dioxane (4 M; 20 mL, 80 mmol) was added and the mixture was heated in an oil bath at 100° C. for 1.5 h. The reaction mixture was allowed to cool. Dichloromethane (200 mL) was added and the mixture was washed with 1:1 water/brine (50 mL), dried (magnesium sulfate), filtered, evaporated, and purified using an ISCO 120 g column, eluting with 5-10% methanol/dichloromethane. Fractions homogeneous for the product were evaporated, and then co-evaporated successively with methanol, diethyl ether and then petroleum ether. The residue was treated with petroleum ether and the mixture was stirred for 20 min. The solid was filtered off and dried under high vacuum at 90° C. for 1 h to give (4S,7R)-2-biphenyl-2-yl-1,7,8,8-tetramethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (612 mg, 47%) as a light yellow solid. APCI(+)-MS (M+H) 359.

Provenance & Evidence