反应详情

To a stirred solution of 5.59 g. (24.6 mmoles) of 4-hydroxy-2-(6-carboxyhexyl) cylopent-2-en-1-one (Example 94) and 20.7 g. (246 mmoles) of dihydropyran in 100 ml. of methylene chloride at 20° C. is added 47 mg. (0.246 mmoles) of p-toluenesulfonic acid monohydrate in one portion. The temperature is maintained at 20°-25° C. by cooling and is stirred for one hour at that temperature. The solution is diluted with 200 ml. of ether and poured into a mixture of 40 ml. of saturated sodium bicarbonate solution, 40 ml. of saturated sodium chloride solution, and 80 ml. of water. The phases are separated, and the aqueous phase is extracted with additional ether. The total extract is washed successively with water and saturated sodium chloride solution, dried over potassium carbonate, and freed of volatile matter by concentration at reduced pressure to give an oil, λmax.MeOH =223 mu (9500); νmax. 1730 (ester carbonyl group), 1705 (ketone carbonyl group), and 1030 cm-1 (tetrahydropyranyloxy groups).

1. temperatureThe temperature is maintained at 20°-25° C.
2. temperatureby cooling
3. additionThe solution is diluted with 200 ml
4. customThe phases are separated
5. extractionthe aqueous phase is extracted with additional ether
6. extractionThe total extract
7. washis washed successively with water and saturated sodium chloride solution
8. dry with materialdried over potassium carbonate
9. concentrationfreed of volatile matter by concentration at reduced pressure
10. customto give an oil, λmax