Naphthalene-based environmentally sensitive fluorescent 8-substituted 2'-deoxyadenosines: application to DNA detection.

We synthesized various C8-naphthylethynylated 2'-deoxyadenosine derivatives and investigated their photophysical properties. Among them, cyano- and N,N-dimethylamino-substituted 8-naphthylethynylated 2'-deoxyadenosine derivatives ((cn)A and (dn)A) showed strong fluorescence with high quantum yields and a remarkable solvatofuorochromicity. In particular, fluorescence of N,N-dimethylamino-substituted (2,6dn)A was not quenched by neighboring guanines (Gs) when incorporated in DNA duplexes, in contrast to (cn)A. We developed a new fluorescent probe containing (2,6dn)A that can be used for the detection of target DNA via a bulge formation regardless of the neighboring sequences.