反应详情

3-Acetyl-2H-chromene (0.5 mole) is dissolved in 250 ml ethanol, while warming. N-methyl-piperazine hydrochloride (0.4 mole) in ethanol (250 ml) and concentrated hydrochloric acid (1 ml) are added thereto. Trioxymethylene (3 moles) is added portionwise over 2 hours, and the resulting material is refluxed overnight. A pale yellow precipitate forms gradually. After cooling, the precipitate is filtered off, washed with ethanol and then with ether, after which it is dried in a desiccator at 90° C. and recrystallized from the minimum amount of water. M.p.=228° C.

1. temperaturewhile warming
2. additionTrioxymethylene (3 moles) is added portionwise over 2 hours
3. temperaturethe resulting material is refluxed overnight
4. temperatureAfter cooling
5. filtrationthe precipitate is filtered off
6. washwashed with ethanol
7. dry with materialwith ether, after which it is dried in a desiccator at 90° C.
8. customrecrystallized from the minimum amount of water