A naphtho[2,1-b]furan as a new fluorescent label: synthesis and spectral characterisation

A fluorescent naphthofuran was synthesised from an oxobenzopyran by alkaline ring contraction and coupled with various l-amino acids at their N-terminus or at side-chain functional groups, in order to evaluate its applicability as a fluorescent label for biomolecules and in peptide synthesis. Fluorescence data were collected for all derivatives, which were found to be moderately fluorescent and having moderate to good fluorescence quantum yields.