Synthesis of ethynylpyrene-modified 3-deaza-2′-deoxyguanosines as environmentally sensitive fluorescent nucleosides: Target DNA-sequence detection via changes in the fluorescence wavelength

Novel pyrene-labeled environmentally sensitive fluorescent (ESF) nucleosides ^1p3zG (1a) and ^2p3zG (1b)] possessing the 3-deazaguanine skeleton were synthesized. Among them, ^1p3zG (1a) exhibited longer fluorescence emission wavelengths compared with the previously reported naphthalene-modified ESF nucleoside ^3nzG (48–71?nm longer in polar solvents) and showed remarkable solvent-polarity-sensitive fluorescence properties. Oligodeoxynucleotide (ODN) probes containing ^1p3zG (1a) clearly discriminated target DNAs by the change in the emission wavelength and intensity through monitoring the microenvironmental change around the DNA minor groove. Thus, these pyrene-labeled ESF nucleosides can be applied in gene detection and molecular diagnostics, as well as in the structural analysis of nucleic acids.