反应详情

19.2 g (100 mmol) of methyl 2-methylbenzoylacetate and 17.7 g of triethyl orthoformate in 40 ml of ethanol plus 0.4 ml of concentrated sulfuric acid are refluxed for 16 hours. After cooling, 2 ml of pyridine are added and the mixture is then concentrated. The residue is taken up in methyl t-butyl ether and extracted 2×with water. The organic phase is dried over sodium sulfate and concentrated. The crude product contains in addition to the title compound about 15% of the corresponding (E) methyl ester (Compound No. 1.47). Distillation results in 16.5 g (75%) of the title compound as colorless oil. 1H-NMR (CDCl3): δ=1.05 (3H, t); 1.37 (3H, t); 2.25 (3H, s); 3.97 (2H, q); 3.99 (2H, q); 5.32 (1H, s); 7.1-7.3 (4H, m) ppm.

1. temperatureAfter cooling
2. concentrationthe mixture is then concentrated
3. extractionextracted 2×with water
4. dry with materialThe organic phase is dried over sodium sulfate
5. concentrationconcentrated
6. additionThe crude product contains in addition to the title compound about 15% of the corresponding (E) methyl ester (Compound No
7. distillationDistillation