Hydrochloric Acid → HCID 16116996, compound

Participants

Reaction Conditions

Reaction Steps

Triethylamine (1.3 mL, 9.33 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; 905 mg, 4.22 mmol) in 1,2-dichloroethane (8 mL) over 1 min. A solution of N′-(2,3-dichloro-phenyl)-N-methyl-hydrazinecarboxylic acid tert-butyl ester (775.8 mg, 2.66 mmol) in 1,2-dichloroethane (14 mL) was added. 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 30 min. The reaction mixture was cooled. A solution of HCl in dioxane (4 M; 10 mL, 40 mmol) was added and the mixture was heated at reflux for 1 h and allowed to cool. Dichloromethane (150 mL) was added and the mixture was washed with 1:1 water/brine (30 mL), dried (magnesium sulfate), filtered, evaporated, and purified using an ISCO 120 g column, eluting with 20-100% ethyl acetate/hexanes. Fractions homogeneous for the product were evaporated, and then co-evaporated with methanol and then diethyl ether. The residue was dried under high vacuum at 70° C. overnight to give (4S,7R)-2-(2,3-dichloro-phenyl)-1,7,8,8-tetramethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (332 mg, 36%) as a white solid. ES(+)-MS (M+H) 351.

Provenance & Evidence