Functionalized bispyridoneannelated BODIPY – Bright long-wavelength fluorophores

A simple approach to the modification of BODIPY nucleus has been developed. The method is based on the reaction of monofun≿tionalized acetaldehyde-substituted dye with primary amines or anilines followed by cyclization of enamine intermediates. This procedure allowed preparing a series of new stable intensive long-wavelength BODIPY derivatives (λem = 680–720 nm) with two functional substituents useful for various practical purposes, including bioconjugation and other biomedical applications.