反应详情

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.

1. customprepared
2. temperaturemaintained
3. customat about −15° C
4. stirringstirring
5. temperaturewhile cooling at −15° C
6. waitThe mixture was kept at room temperature for about 12 hours
7. customthe two layers were separated
8. washdichloromethane was washed with water and brine
9. dry with materialdried over sodium sulfate
10. customevaporated
11. customThe residue was chromatographed on silica gel (cyclohexane:ethyl acetate=20:30)