反应详情

温度

0 °C

36.5 g. of 8-hydroxy-3,7-dimethyl-octa-2,4,6-trien-1-oic acid ethyl ester are dissolved in 380 ml. of ether. The solution is cooled to 0° C., and after the addition of 3 drops of pyridine treated dropwise with 28.6 g. of phosphorous tribromide in 120 ml. of hexane. The mixture is stirred for 20 minutes at 0° C., then poured onto ice water and extracted with ether. The ether extract is washed successively with water, a saturated aqueous sodium bicarbonate solution and again with water, dried over sodium sulfate and evaporated. There is obtained 8-bromo-3,7-dimethyl-octa-2,4,6-trien-1-oic acid ethyl ester, which is processed as follows:

1. additiontreated dropwise with 28.6 g
2. additionpoured onto ice water
3. extractionextracted with ether
4. extractionThe ether extract
5. washis washed successively with water
6. dry with materiala saturated aqueous sodium bicarbonate solution and again with water, dried over sodium sulfate
7. customevaporated