New Size‐Expanded Fluorescent Thymine Analogue: Synthesis, Characterization, and Application

Here, the synthesis, photophysical characterization, and application of a new size‐expanded thymine nucleoside, dioxT, is described. dioxT has desirable qualities as a T surrogate, including excellent quantum yield (0.36) and high environmental sensitivity. When incorporated into single‐ and double‐stranded DNA, dioxT showed excellent photophysical characteristics including a high quantum yield (average 0.20), and unlike BgQ, demonstrated dependence on neighboring bases without significant destabilization of the duplex. Interestingly, the matched base pair of adenine (A) and dioxT has the unique property that it exhibits higher fluorescence than mismatched base pairs, and dioxT has self‐quenching effects. As one example of the possible applications of these promising features, single nucleoside polymorphism typing is demonstrated for discrimination of A by using dioxT. The results suggest that dioxT can be used for a broad range of applications in chemical biology. Fluorescent thymine: The synthesis, photophysical characterization, and application of a new size‐expanded thymine nucleoside, dioxT, is described. dioxT has desirable qualities as a T surrogate, including excellent quantum yield (0.36) and high environmental sensitivity. When incorporated into single‐ and double‐stranded DNA, dioxT showed excellent photophysical characteristics including a high quantum yield (average 0.20).