Rational Design of Latent Fluorophores from Water-Soluble Hydroxyphenyltriazine Dyes Suitable for Lipase Sensing

The phenol residue of water‐soluble 2‐(2′‐hydroxy‐5′‐dimethylaminobenzyl)‐4,6‐dimethylamino‐1,3,5‐triazine is masked by an enzyme‐labile protecting group constructed with a self‐immolative para‐hydroxybenzyl alcohol. The fluorescence of the dyes is restored with lipases under physiological conditions without aggregation or precipitation of the fluorescent dyes. Derivatives of 2‐(2′‐hydroxy‐5′‐dimethylaminobenzyl)‐4,6‐dimethylamino‐1,3,5‐triazine were synthesized by an original multistep protocol that afforded, after quaternization of the N,N‐dimethylaminobenzyl moiety, water‐soluble fluorescent dyes. These fluorophores exhibited excited‐state intramolecular proton transfer and large Stokes …