Design of an environmentally sensitive fluorescent 8-aza-7-deaza-2′-deoxyadenosine derivative with dual fluorescence for the specific detection of thymine

A novel environmentally sensitive fluorescent (ESF) purine nucleoside, ^cnaA, was synthesized and its photophysical properties were investigated. The base-modified fluorescent nucleoside ^cnaA exhibited remarkable solvatochromicity and environmentally sensitive dual fluorescence. By using ^cnaA, we have developed highly thymine (T) selective fluorescent DNA probes that can sense the corresponding T in a target DNA/RNA sequence, as measured by a distinct change in emission wavelength.