反应详情

温度

-40 °C

Ethyl 3-amino-1-methylpyrazole-4-carboxylate, prepared by the method of Schmidt et al., Helvetica Chim. Acta. 42 349 (1959), (12.5 g, 7.40 mmol) was dissolved in 80 mL of 1,3-dimethyl-3,4,5,6-tetrahydro2(1H)-pyrimidinone (DMPU) and cooled to -40° C. A 1M solution of sodium hexamethyldisilazide in tetrahydrofuran (80 mL, 8.0 mmol) was added dropwise. After 8 minutes at -35° C., the reaction was cooled to -40° C. and 13.16 g (10.8 mmol) of allyl bromide was added dropwise. The reaction mixture was allowed to warm to 10° C. over 90 minutes. Water was added and the mixture was extracted with ether. The combined organic extracts were washed with water (3×), dried over sodium sulfate and concentrated in vacuo to afford a mixture of mono- and di-allyl products plus 10% unreacted starting material. Separation by column chromatography on silica gel eluting with 30% ethyl acetate in hexane afforded 5.26 g (34%) of the title compound as a colorless oil.

1. temperaturethe reaction was cooled to -40° C.
2. temperatureto warm to 10° C. over 90 minutes
3. extractionthe mixture was extracted with ether
4. washThe combined organic extracts were washed with water (3×)
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated in vacuo
7. customto afford
8. customSeparation by column chromatography on silica gel eluting with 30% ethyl acetate in hexane