反应详情

A mixture of 215 mg of the product of Example 43, 15 mg of 4-dimethylamino-pyridine, 1 ml of pyridine and 0.5 ml of acetic acid anhydride was stirred at room temperature for 30 minutes and was then poured into 20 ml of a saturated aqueous sodium bicarbonate solution. After stirring for 20 minutes, the mixture was extracted with ethyl acetate. The organic phase was washed with water and evaporated to dryness and the pyridine and residual acetic acid were distilled. The residue was chromatographed on silica and eluted with a 65-35 methylene chloride-ethyl acetate mixture. The residue with a Rf=0.35 was taken up in isopropanol, partially concentrated, iced and vacuum filtered to obtain after drying, 210 mg of the desired product melting at 99° C. to 100° C.

1. stirringAfter stirring for 20 minutes
2. extractionthe mixture was extracted with ethyl acetate
3. washThe organic phase was washed with water
4. customevaporated to dryness
5. distillationthe pyridine and residual acetic acid were distilled
6. customThe residue was chromatographed on silica
7. washeluted with a 65-35 methylene chloride-ethyl acetate mixture
8. concentrationpartially concentrated
9. filtrationiced and vacuum filtered
10. customto obtain
11. customafter drying