A nucleobase-discriminating pyrrolo-dC click adduct designed for DNA fluorescence mismatch sensing

New pyrrolo-dC click adducts (4 and 5) tethered with a 1,2,3-triazole skeleton were synthesized and oligonucleotides were prepared. The triazole system was either directly linked to the pyrrolo moiety (5) or connected via an n-butyl linker (4). The quantum yield of nucleoside 5 (Φ=0.32), which is 10 times higher than those of 8-methylpyrrolo-dC (1 b, Φ=0.026) or the long linker derivative 4 (Φ=0.03), is maintained in oligonucleotides. Compound 5 was used as a nucleobase-discriminating fluorescence sensor in duplex DNA. Excellent mismatch discrimination was observed when 5 was positioned opposite the four canonical nucleosides. Compound 5 has the potential to be used for SNP detection in long DNA targets when conventional techniques such as high resolution melt analysis fail.