Abstract
Coumarin derivatives were prepared with a monosubstituent of hydroxyl, methoxyl, methyl, or acetoxyl group in one of the ortho (5), meta (6), or para (7) position of α, β-unsaturated carbonyl group and disubstituents of two hydroxyl, methoxyl, or acetoxyl groups in 5, 7-, 6, 7-, or 7, 8-position. The ultraviolet absorption spectra were determined in 95% ethanol solution. Methyl and acetoxyl derivatives showed spectra similar to that of coumarin, irrespective of the position or number of the substituents. Hydroxyl and methoxyl derivatives, on the other hand, showed extremely complicated spectra according to the position and number of substituents present. Assuming that the two absorption bands of coumarin at 270mμ and 312mμ were those of benzene around 200mμ and 240-260mμ that had shifted to these regions, the ultraviolet absorption spectra of these coumarin derivatives were qualitatively explained according to the latest theory regarding light absorption.
