Triethylamine → 1-Aminocarbonyl-3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydroindazole

Participants

Reaction Steps

A solution of trichloromethyl chloroformate (0.37 ml, 3.03 mmol) in 3 ml of dichloromethane was added dropwise to a solution of 3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indazole (0.4 g, 2.25 mmol), prepared as described in example 15, and triethylamine (0.42 ml, 3.03 mmol) maintained under magnetic stirring and inert atmosphere at about −15° C. The reaction mixture was allowed to warm to room temperature and stirring was continued for about 3.5 hours. A solution of 32% amonium hydroxide (10 ml) was then added while cooling at −15° C. The mixture was kept at room temperature for about 12 hours and the two layers were separated; dichloromethane was washed with water and brine, dried over sodium sulfate and evaporated. The residue was chromatographed on silica gel (cyclohexane:ethyl acetate=20:30), to yield the title compound as a colourless solid (0.170 g, 36%): m.p. 173-175° C.

Provenance & Evidence