Abstract
A dinucleoside monophosphate, 2'-azido-2'-deoxyadenylyl-(3'-5')-2'-azido-2'-deoxyadenosine (II) was synthesized by condensation of the 5'-monomethoxytrityl (IV) and N6, 3'-O-dibenzoyl-5'-phosphoryl derivatives (III) of 2'-azido-2'-deoxyadenosine using DCC as a condensing reagent. The ultraviolet absorption properties of compound II were similar to those of ApA. The circular dichroism (CD) spectrum of II was also similar to that of ApA in pattern, but the magnitudes of the CD bands were about a half of those of ApA. 1H nuclear magnetic resonance signals appeared in the expected position for a dimer, and the dimerization shifts were similar to those of ApA. However, the 3'-linked residue of compound II showed a J1'-2' value significantly higher than that of ApA. These results suggest that compound II takes an anti-anti, right-handed stacked conformation similar to that of ApA, but with decreased stability or with a significantly different stacking geometry.
