Chemistry on Boranils: an entry to functionalized fluorescent dyes.

A Boranil fluorophore bearing a nitro-phenyl group has been selectively reduced to its anilino form and then successfully converted to amide, imine, urea, and thiourea derivatives which are fluorescent dyes. Its isolated isothiocyanate intermediate derivative was used in a model labeling experiment with Bovine Serum Albumin (BSA). The purified labeled-BSA exhibits strong luminescence (Φ(f) = 47%) in a phosphate buffer at pH = 7.4.