One-Step Halogenation at the 2'-Position of Uridine, and Related Reactions of Cytidine and N⁴-Acetylcytidine

Abstract

The reaction of uridine with acyl bromide in acetonitrile (or ethyl acetate) afforded 3', 5'-di-O-acyl-2'-bromo-2'-deoxyuridine (II, V) in good yield, which was converted to 2'-deoxyuridine by hydrogenation and subsequent deacylation. A silmiar reaction of N⁴-acetylcytidine with acetyl bromide yielded 1-(2, 5-di-O-acetyl-3-bromo-3-deoxy-β-D-xylofuranosyl)-N⁴-acetylcytosine (VIII), which was converted to 3'-deoxycytidine (X) by hydrogenation and subsequent deacylation with a concomitant formation of 2', 3'-dideoxycytidine (XII) and to 1-β-D-arabinofuranosyl cytosine (XI) by treatment with potassium hydroxide in ethanol. A similar reaction of cytidine with acyl bromide gave 2, 2'-anhydro-1-(3, 5-di-O-acyl-β-D-arabinofuranosyl) cytosine hydrobromide (XIV, XVI). These reaction mechanisms were also presented.