反应详情

A mixture of 4-phenylbenzaldehyde (5.17 g, 28.4 mmol), malonic acid (4.0 g), pyridine (20 ml), and piperidine (0.5 ml) was heated until gas evolution began. Heating was continued until gas evolution ceased (about 30 minutes at 90°-100° C.). The mixture was cooled, and the solid product triturated with boiling methanol (150 ml) and enough concentrated HCl to make the mixture acidic. The mixture was cooled, and the product collected by filtration, washed with water and methanol, and dried in vacuo to provide 4-phenylcinnamic acid (4.85 g, 76% yield), mp 220°-225° C. This material was dissolved in ethanol (150 ml) containing concentrated sulfuric acid (0.5 ml) and triethyl orthoacetate (3.5 ml), and refluxed for 24 hours. Removal of the solvent and recrystallization of the residue from methanol-water provided the ethyl ester (5.0 g, 92% yield), mp 88°-89° C.

1. temperaturewas heated until gas evolution
2. temperatureHeating
3. custom(about 30 minutes at 90°-100° C.)
4. temperatureThe mixture was cooled
5. customthe solid product triturated with boiling methanol (150 ml) and enough concentrated HCl
6. temperatureThe mixture was cooled
7. filtrationthe product collected by filtration
8. washwashed with water and methanol
9. customdried in vacuo