反应详情

To a solution of 64 g (0.75 mol) cyanoacetic acid and 250 ml of acetic anhydride was added 70 g (0.7 mol) of cyclopropylurea. The solution was stirred at 60°-70° C. for 2 hours. After cooling white crystals were filtered off and washed with ethanol. Yield 76.7 g (66%) (I). This was suspended in 200 ml of hot water and 55 ml of 5N NaOH was added in portions so the solution the whole time was basic. The reaction mixture was refluxed for 20 minutes and then neutralized with 5N HCl. After cooling, white crystals were filtered off. Yield 31.7 g (42%) (II) NMR.

1. temperatureAfter cooling white crystals
2. filtrationwere filtered off
3. washwashed with ethanol
4. addition55 ml of 5N NaOH was added in portions so the solution the whole time
5. temperatureThe reaction mixture was refluxed for 20 minutes
6. temperatureAfter cooling
7. filtrationwhite crystals were filtered off