3-Benzoyl-4-benzylamino-7-dimethylaminocoumarin was synthesized and its conformation in solid state and solution was determined. While the X-ray crystal analysis showed an aromatic π-π stacking interaction in the solid state, the proton NMR studies suggested the presence of an intramolecular hydrogen bonding in solution. Adjacent functional group modifications through N-methylation, reduction of carbonyl group, or replacing the coumarin moiety to dimedone, all resulted in disrupting the π-π stacking conformation. Upon UV irradiation, the 7-methylamino group can be oxidized by molecular oxygen to the corresponding formamide in the absence of any external photosensitizers. ? 2013 Elsevier Ltd. All rights reserved.
