反应详情

A mixture of 3,4-diphenylpyrazole (2.2 g), ethyl 8-bromooctanoate (5.5 g) and potassium carbonate (3.7 g) in dry butanone (50 ml) was heated at reflux temperature for 44 hours. The mixture was filtered and the filtrate evaporated to an oil which was chromatographed on silica gel (hexane/ethyl acetate). The oil obtained was heated at reflux temperature in a mixture of ethanol and 2N sodium hydroxide (1:1) for 1 hour. The ethanol was evaporated and the aqueous residue was acidified with dilute hydrochloric acid to pH 3, extracted with dichloromethane, dried over magnesium sulphate and evaporated to a solid. This was recrystallised from dichloromethane/ether to give 8-(3,4-diphenylpyrazol-1-yl)octanoic acid (0.48 g, 13%) as colourless crystals, m.p. 114°-5° C. Found: C, 76.02; H, 7.25; N, 7.63%; C23H26N2O2 requires: C, 76.21; H, 7.23; N. 7.73%

1. temperaturewas heated
2. temperatureat reflux temperature for 44 hours
3. filtrationThe mixture was filtered
4. customthe filtrate evaporated to an oil which
5. customwas chromatographed on silica gel (hexane/ethyl acetate)
6. customThe oil obtained
7. temperaturewas heated
8. temperatureat reflux temperature
9. customThe ethanol was evaporated
10. extractionextracted with dichloromethane
11. dry with materialdried over magnesium sulphate
12. customevaporated to a solid
13. customThis was recrystallised from dichloromethane/ether