反应详情

温度

-30 °C

Acetic anhydride (20 ml., 212 mmol) was added gradually to fuming nitric acid (20 ml., 477 mmol) with efficient stirring, while the temperature was kept between -30° to -35° C. by external cooling. While the mixture was being stirred vigorously, 1-(3,5-di-O-acetyl-β-D-arabinofuranosyl)-N4 -acetylcytosine (10 g., 27 mmol) was added in batches to the homogeneous mixture while maintaining the temperature at about -30° C. The clear reaction mixture was allowed to warm gradually to 0° C. After being stirred for 30 minutes at this temperature, the solution was poured into a mixture of ice and saturated aqueous (NH4)2SO4 solution (250 ml.) that was stirred until all the ice had melted. The aqueous phase was then extracted with ethyl acetate (3×250 ml). The combined extracts were washed with saturated aqueous sodium bicarbonate (2×200 ml.) and water (3×200 ml.), and was then dried (Na2SO4) Crude 1 -(2-O-nitro-3,5-di-O-acetyl-β-D-arabinofuranosyl)-N4 -acetylcytosine (10.66 g., 95%) was obtained by removing the ethyl acetate under reduced pressure. The solid residue was crystallized from ethyl acetate to obtain pure 1-(2-O-nitro-3,5-di-O-acetyl-β-D-arabinofuranosyl)-N4 -acetylcytosine (9.65 g., 86% yield): m.p. 159.7°-160.6° C.

1. customwas kept between -30° to -35° C. by external cooling
2. temperatureto warm gradually to 0° C
3. stirringAfter being stirred for 30 minutes at this temperature
4. extractionThe aqueous phase was then extracted with ethyl acetate (3×250 ml)
5. washThe combined extracts were washed with saturated aqueous sodium bicarbonate (2×200 ml.) and water (3×200 ml.)
6. dry with materialwas then dried (Na2SO4) Crude 1 -(2-O-nitro-3,5-di-O-acetyl-β-D-arabinofuranosyl)-N4 -acetylcytosine (10.66 g., 95%)
7. customwas obtained
8. customby removing the ethyl acetate under reduced pressure
9. customThe solid residue was crystallized from ethyl acetate