The silver salt of N-acetylcytosine condenses with 3,4,6-tri-O-acetyl-2-deoxy-2-(2′,4′-dinitroanilino)-α-D-glucopyranosyl bromide to give an O-glycoside, predominantly the β-isomer, also obtained by acetylation of the analogous product from the silver salt of cytosine. This O-glycoside, which does not rearrange to an N-glycoside when treated with mercuric bromide in xylene, is the major product of a similar reaction with N-acetylcytosinemercury, although this mercury salt has previously yielded N-glycosides exclusively. The corresponding N-glycoside is only a minor product in the present instance.