Reactions of cytosine and cytidine with O-substituted hydroxylamines

Abstract

Reactions of cytosine (Ia) and cytidine (Ib) with a wide variety of O-alkylhydroxylamines (II) are reported. At pH 4 in methanol–water and in the presence of an excess of hydroxylamine, the major product in each case is the N(4)-alkoxy-6-alkoxyamino-5,6-dihydro-derivative (IVa or b). Compounds containing primary and secondary alkyl or arylalkyl and tertiary alkyl groups in the hydroxylamine function are described and characterised by analysis and u.v., i.r., and ¹H and ¹³C n.m.r. spectra. Treatment of the addition–substitution products (IVa) with acid gives N(4)-alkoxycytosines (Va) by elimination of O-alkylhydroxylamine. The reaction of cytosine with bis-1,6-amino-oxyhexane is also reported.