Water → N'-(3,5-dichloro-phenyl)-N'-((1R,4R)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl)-hydrazinecarboxylic acid tert-butyl ester

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Reaction Steps

Triethylamine (10.75 mL, 77 mmol) was added in two portions 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; 5.5 g, 25.6 mmol) in dichloromethane (55 mL), giving a thick precipitate. N′-(3,5-dichloro-phenyl)-hydrazinecarboxylic acid tert-butyl ester (Intermediate 35; 5.5 g, 19.8 mmol) was added, along with dichloromethane (25-30 mL). The reaction mixture was placed in an oil-bath at 50° C., heated at this temperature overnight and then allowed to cool to room temperature and stir for 20 min. The reaction mixture was poured into water (100 mL) and two layers were separated. The organic layer was washed with water (100 mL) and brine (100 mL), dried (magnesium sulfate), filtered, evaporated, and then dried under high vacuum to give N′-(3,5-dichloro-phenyl)-N′-((1R,4R)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl)-hydrazinecarboxylic acid tert-butyl ester (10 g, 111% of the expected amount) as an orange foam, which was used directly in the next step without further purification.

Provenance & Evidence