反应详情

A solution of the pyrazole of Example 11 (283 mg, 1.00 mmol) in water (1 ml) and ethanol (0.5 ml) was treated with 37% W/w aqueous formaldehyde solution (112 μL, 1.50 mmol) and the resulting mixture was stirred at room temperature for 18 hours. The reaction was then stirred under reflux for 2 hours. The reaction mixture was diluted with water and extracted with dichloromethane. The organic extract was dried over anhydrous magnesium sulphate, filtered and concentrated under reduced pressure. The crude material was purified by flash chromatography on silica gel eluting with pentane:ethyl acetate (2:1, by volume) to afford the title compound (231 mg) as a white solid, m.p. 117–118° C.

1. stirringThe reaction was then stirred
2. temperatureunder reflux for 2 hours
3. extractionextracted with dichloromethane
4. extractionThe organic extract
5. dry with materialwas dried over anhydrous magnesium sulphate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe crude material was purified by flash chromatography on silica gel eluting with pentane:ethyl acetate (2:1, by volume)