反应详情

33.6 g (131.7 mmol) of the compound from Example VI are dissolved in 320 ml of dimethoxyethane and the solution is stirred with 197.6 mmol (27.6 ml) of triethylamine. After 30 minutes, 19.75 ml (197.5 mmol) of ethyl chlorocarbonate are added dropwise at 20°-30° C. The mixture is subsequently stirred for 30 minutes and the salt is filtered off with suction and washed with dimethoxyethane. The filtrate is concentrated end the residue is dissolved in a mixture of 320 ml of ethanol and 160 ml of water, and a solution of 9.25 g of sodium borohydride in 54 ml of water is added dropwise at 15°-18° C. The mixture is stirred at room temperature for 1 hour and the salt is filtered off with suction and washed with ethanol and water. The filtrate is concentrated to one third, methylene chloride and water are added and the phases are separated. The organic phase is washed 3 times with water, dried and concentrated. 26 g of a pale brown oil are obtained, which is employed without further purification.

1. filtrationthe salt is filtered off with suction
2. washwashed with dimethoxyethane
3. concentrationThe filtrate is concentrated end the residue
4. dissolutionis dissolved in a mixture of 320 ml of ethanol and 160 ml of water
5. additiona solution of 9.25 g of sodium borohydride in 54 ml of water is added dropwise at 15°-18° C
6. stirringThe mixture is stirred at room temperature for 1 hour
7. filtrationthe salt is filtered off with suction
8. washwashed with ethanol and water
9. concentrationThe filtrate is concentrated to one third, methylene chloride and water
10. additionare added
11. customthe phases are separated
12. washThe organic phase is washed 3 times with water
13. customdried
14. concentrationconcentrated