反应详情

A solution of 1-(2-O-nitro-β-D-arabinofuranosyl)cytosine [6.6 g., 23 mmol. which was a white foam that was homogeneous by TLC (upper phase of 4:2:1=ethyl acetate:H2O:1-propanol)] in methanol was acidified with concentrated hydrochloric acid until the pH of the solution was ~1.0. A white solid began to separate immediately. The solvent was removed under reduced pressure, and the resulting residue was coevaporated with methanol (3×200 ml). The product thus obtained was dried in vacuo and crystallized from a mixture of 1:1=absolute ethanol: 96% ethanol. The crystals were collected by centrifugation to obtain pure 1-(2-O-nitro-β-D-arabinofuranosyl)cytosine hydrochloride (4.83 g., 65%): m.p.>170° C. dec. The salt had these physical characteristics:

1. customto separate immediately
2. customThe solvent was removed under reduced pressure
3. customThe product thus obtained
4. customwas dried in vacuo
5. customcrystallized from a mixture of 1:1=absolute ethanol
6. customThe crystals were collected by centrifugation