反应详情

To a stirred solution of dimethyl acetonedicarboxylate (44.1 ml, 0.3 mole) and p-toluene-sulfonic acid (0.19 g, 1 mmol) in benzene (50 ml) was bubbled NH3 gas for 30 min. The mixture was refluxed with azeotropic removal of water using Dean-Stark trap. The bubbling of NH3 gas and azeotropic removal of water was repeated three times to give a total 5 ml of water. The reaction mixture was diluted with benzene and filtered through celite. The filtrate was concentrated to give an amber oil, 50.75 g. An equal volume of ether was added to this oil and hexane added until cloudy, and stirred slowly overnight to afford a crystalline product. This crystalline was collected by filtration and washed once with 1/1 of ether/hexane to give 44.55 g (85.75%) of crystalline, mp 47°-50° C.

1. customThe bubbling of NH3 gas and azeotropic removal of water
2. customto give a total 5 ml of water
3. filtrationfiltered through celite
4. concentrationThe filtrate was concentrated
5. customto give an amber oil, 50.75 g
6. additionadded until cloudy
7. customto afford a crystalline product
8. filtrationThis crystalline was collected by filtration
9. washwashed once with 1/1 of ether/hexane
10. customto give 44.55 g (85.75%) of crystalline, mp 47°-50° C.