Abstract
Reaction of 2′,3′-O-isopropylideneadenosine (1) with p-NCC6H4COCl in 1:6 Et3N–CH2Cl2 afforded the cyanoimidazole nucleoside 8 (53%) and the 8,5′-O-cycloadenosine derivative 7 (29%). Treatment of N6,N6-di-p-toluyl-2′,3′-O-isopropylideneadenosine (23) with ZnBr2 in p-dioxane resulted in acyl migration from N6 to N7 to give the cycloadenosine derivative 4. The coordination site of the zinc cation on the base moiety of adenosine derivatives was determined by 15N nmr spectra.