Fluorogenic probes for chemical transformations: 9-anthracene derivatives for monitoring reaction progress by an increase in fluorescence

The development of fluorogenic probes for chemical transformations bearing anthracene as a fluorescent core moiety is reported. Fluorogenic probes were designed by linking anthracene with functional groups used for reactions of interest. Each fluorogenic probe, possessing a reaction group such as aldehyde, α,β-unsaturated ketone, or imine at the 9-position of the anthracene, showed no or very low fluorescence. Reaction products of the probes, including aldol and addition products, were highly fluorescent. The products showed more than 1000-fold higher fluorescence than did the fluorogenic probes under the same conditions. The utility of the fluorogenic probes was demonstrated in monitoring the progress of a catalyzed aldol reaction.