Hydrochloric Acid → HCID 57941305, compound

Participants

Reaction Conditions

Reaction Steps

Triethylamine (1 mL, 7.2 mmol) was added dropwise to a solution of N′-(2,5-difluoro-phenyl)-N′-methyl-hydrazinecarboxylic acid tert-butyl ester (305 mg, 1.2 mmol) in 1,2-dichloroethane (6 mL) over 1 min. The reaction mixture was stirred for 5 min and then a solution of (1R,4R)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl chloride (Intermediate 20; 800 mg, 3.7 mmol) in 1,2-dichloroethane (14 mL) was added over 2 min. The reaction mixture was heated in an oil bath at 50° C. for 1 h. The solution was allowed to cool and a solution of HCl in dioxane (4 M; 6 mL, 24 mmol) was added and the mixture was heated at reflux for 1.5 h and then allowed to cool to room temperature. The solvent was evaporated and the residue was purified by preparative HPLC to give a yellow foam. This was taken up in ethyl acetate and washed with water. The organic layer was evaporated and the residue was further purified on an ISCO system, eluting with 50-90% ethyl acetate/hexanes. Fractions homogeneous for the product were evaporated, co-evaporated successively with methanol, and diethyl ether, and then dried under high vacuum at 75° C. overnight to give (4S,7R)-2-(2,5-difluoro-phenyl)-1,7,8,8-tetramethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (105 mg, 27%) as a white solid. ES(+)-MS (M+H) 319.

Provenance & Evidence