Trifluoroacetic acid → (4r,7s)-2-(2-Chloro-4-fluoro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one

Participants

Reaction Conditions

Reaction Steps

Trifluoroacetic acid (15 mL) was added in two portions to a cooled (0° C.) solution of N′-(2-chloro-4-fluoro-phenyl)-N′-((1S,4S)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl)-hydrazinecarboxylic acid tert-butyl ester (˜7.2 mmol) in dichloromethane (15 mL). The reaction mixture was stirred at 0° C. for 5 min and then at room temperature for 2 h. The reaction mixture was evaporated (using high vacuum in the end). Dichloromethane (100 mL) was added to the residue and the solution was washed with water (4×50 mL), and brine (50 mL), dried (magnesium sulfate), filtered, and evaporated to give (4R,7S)-2-(2-chloro-4-fluoro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (2.6 g, 113% of the expected amount) as a tan solid. This was used directly in subsequent steps without further purification.

Provenance & Evidence