Interaction of cyanine dyes with nucleic acids. Part 19: new method for the covalent labeling of oligonucleotides with pyrylium cyanine dyes

New chemistry for the fluorescent labeling of oligonucleotides with cyanine dyes is proposed. It is based on the use of pyrylium salts as amine-specific reagents. Monomethyne pyrylium cyanine dye 1 was covalently linked to 5′-aminoalkyl modified oligonucleotide, with simultaneous conversion of the non-fluorescent dye 1 into fluorescent pyridinium cyanine structure 2.