Reactions of 3-benzoyl-7-dimethylamino-4-hydroxycoumarin and their potential applications in solution- and solid-phase synthesis.

3-Benzoyl-7-dimethylamino-4-hydroxycoumarin was synthesized and its UV-vis spectra in various mixtures of MeOH and CH(2)Cl(2) were measured. The diketone lactone exists mainly in the exocyclic-enol form in protic solvents and the endocyclic-enol form in nonpolar solvents. Acetylation, amination and methylation products of the diketone lactone were characterized by X-ray crystallography. The results indicated that acetylation of coumarin-based diketone lactones occurs exclusively at the 4-hydroxy group, but that amination takes place specifically at the C-3 carbonyl group. Among the prepared compounds, amination products were found to exhibit photochromic property and colorimetric ion-sensing ability, and methylation product has the potential to function as a primary amine protection group.