Abstract
Preparations of the ring-fused 4-methylcoumarins 2-10 were reexamined, and the nuclear magnetic resonance (NMR), ultraviolet (UV) and fluorescence spectral characteristics were determined. Fluorescence properties were found to be sensitive to the type and the position of the ring fused to the parent 4-methylcoumarin 1. The angularly benzo-fused 3 was highly fluorescent, whereas the linearly benzo-fused 4 and the pyrono-fused 7 and 9 were only weakly fluorescent.
