反应详情

A mixture of ethyl 8-carboxy-12-acetoxyheptadecanoate (31.5 g., 0.079 mole), red mercuric oxide (12.8 g., 0.059 mole), and carbon tetrachloride (200 ml.) is stirred at room temperature while bromine (12.6 g., 0.079 mole) is added dropwise during one hour. The resulting mixture is heated at reflux for one hour. The mixture is then cooled, filtered, washed with dilute hydrochloric acid, water and brine and dried over sodium sulfate. The solution is evaporated in vacuo to leave the product as a yellow residual weighing 24.5 g. The product is purified by chromatography on a column containing 250 g. of silica gel using chloroform as eluting solvent. There is obtained 14.4 g. of purified ethyl 8-bromo-12-acetoxyheptadecanoate, a yellow oil with Rf 0.49 on silica gel thin layer chromatography with chloroform elution. pmr (CDCl3) δ 0.90 (3H,t); 2.03 (3H, s CH3CO); 4.07 (1H, m HCBr); 4.13 (2H, q); 4.92 (1H, m HCO).

1. additionis added dropwise during one hour
2. temperatureThe resulting mixture is heated
3. temperatureat reflux for one hour
4. temperatureThe mixture is then cooled
5. filtrationfiltered
6. washwashed with dilute hydrochloric acid, water and brine
7. dry with materialdried over sodium sulfate
8. customThe solution is evaporated in vacuo
9. customto leave the product as a yellow
10. customThe product is purified by chromatography on a column
11. additioncontaining 250 g
12. washas eluting solvent
13. customThere is obtained 14.4 g
14. washof purified ethyl 8-bromo-12-acetoxyheptadecanoate, a yellow oil with Rf 0.49 on silica gel thin layer chromatography with chloroform elution