Photoactivatable Fluorescein Derivatives Caged with a (3-Hydroxy-2-naphthalenyl)methyl Group

Abstract

The (3-hydroxy-2-naphthalenyl)­methyl (NQMP) group represents an efficient photocage for fluorescein-based dyes. Thus, irradiation of the 6-NQMP ether of 2′-hydroxymethylfluorescein with low-intensity UVA light results in a 4-fold increase in emission intensity. Photoactivation of nonfluorescent NQMP-caged 3-allyloxyfluorescein produces a highly emissive fluorescein monoether. To facilitate conjugation of the caged dye to the substrate of interest via click chemistry, the allyloxy appendage was functionalized with an azide moiety