Partial protection of carbohydrate derivatives. Part 1. Specific N-debenzoylation of fully benzoylated adenosine and cytidine with phenols and alcohols; active N-benzoyl groups

Abstract

Specific N-debenzoylation of N⁶,2′,3′,5′-tetrabenzoyladenosine (1), N⁶,N⁶,2′,3′,5′-pentabenzoyladenosine (3), and N⁴,2′,3′,5′-tetrabenzoylcytidine (4) was achieved by treatment with nitrophenols, phenol, p-methoxyphenol, and a series of alcohols to give the corresponding nucleoside benzoates with free amino-groups in high yields: the reaction can also be regarded as a benzoylation of hydroxy-compounds by nucleoside N-benzoyl groups. On the basis of these results, the order of activity of these nucleoside benzoates was found to be (3) > (1) > (4). N-Benzoylation of 2′,3′,5′-tri-O-benzoyladenosine (2) with 2,4-dinitrophenyl benzoate (5) and of cytidine (6) with the pentabenzoyladenosine (3) gave the tetrabenzoyladenosine (1) and N-benzoylcytidine (7), respectively, in high yields.