反应详情

To a solution of 5 g 5-Hydroxy-1-phenyl-1H-pyrazole-3-carboxylic acid ethyl ester in 12 ml of DMF was added at 0° C. 1.29 g of sodium hydride (60% in mineral oil). After 15 min at this temperature 3.85 g of 1-Bromo-3,3-dimethyl-butan-2-one were added. After 2 h at RT the mixture was poured on ice/water and extracted with ethyl acetate. The organic phase was washed with brine and dried over sodium sulfate followed by evaporation. The residue was taken up in 20 ml of THF and treated with 21.5 ml of 2M NaOH. After 2 h, additional 15 ml 2M NaOH were added. Finally, after 3 h the THF was evaporated and the residue acidified with 2M HCl resulting in the precipitation of a gum. The gum was dissolved in ethyl acetate and coevaporated with toluene. Stirring in ethyl acetate/hepatne 1:1 gave a gummy substance which solidified on evaporation.

1. additionAfter 2 h at RT the mixture was poured on ice/water
2. extractionextracted with ethyl acetate
3. washThe organic phase was washed with brine
4. dry with materialdried over sodium sulfate
5. customfollowed by evaporation
6. additiontreated with 21.5 ml of 2M NaOH
7. additionadditional 15 ml 2M NaOH were added
8. customFinally, after 3 h the THF was evaporated
9. customthe residue acidified with 2M HCl resulting in the precipitation of a gum
10. dissolutionThe gum was dissolved in ethyl acetate
11. customgave a gummy substance which
12. customsolidified on evaporation