Nitric Acid → 1-(2-O-nitro-3,5-di-O-acetyl-beta-D-arabinofuranosyl)-N4-acetylcytosine

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Reaction Conditions

Reaction Steps

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.

Provenance & Evidence