Synthesis of N-[(tert-Butoxy)carbonyl]-3-(9,10-dihydro-9-oxoacridin-2-yl)-L-alanine, a New Fluorescent Amino Acid Derivative

A simple synthesis of a new, highly fluorescent amino acid and of its protected derivative useful in peptide studies is described. The obtained derivative, N-[(tert-butoxy)carbonyl]-3-(9,10-dihydro-9-oxoacridin-2-yl)-L-alanine (6), shows intense long-wave absorption (above 360 nm) and emission (above 400 nm). The quantum yield of fluorescence of the investigated compound is very high, so it can serve as a sensitive analytical probe useful, e.g., in analysis of peptide conformations.