Interaction of cyanine dyes with nucleic acids. 2. Spectroscopic properties of methyleneoxy analogues of Thiazole Orange

A series of asymmetric cyanine dyes based on methylenoxy benzothiazole terminal hetero-cycle was synthesized. Absorption and fluorescent properties of these dyes and their complexes with nucleic acids were investigated. The best results were obtained with 2-[(3-methyl-2(3H)-benzothiazolyliden)-methyl]-5,6-dioxymethylene-3-methylbenzothiaz olium p-toluenesulfonate (Cyan 13). A possible model of binding monomethyne benz-thiazole cyanine dyes with double-stranded nucleic acids is proposed.