3-HYDROXYCOUMARINS - 1ST DIRECT PREPARATION FROM COUMARINS USING A CU-2+ ASCORBIC-ACID O2 SYSTEM, AND THEIR POTENT BIOACTIVITIES

First direct 3-hydroxylation of a coumarin ring via a purely chemical system, previously only possible using cytochrome P-450, was successfully conducted by a Cu2+-ascorbic acid-O2 system; the two 3-hydroxycoumarins obtained were novel compounds, 3-hydroxyscopoletin and 3-hydroxyisoscopoletin. 5-Lipoxygenase and α-D-glucosidase inhibitory activities of coumarins greatly increased through 3-hydroxylation. 3-Hydroxyscopoletin and 3-hydroxyumbelliferone had a high inhibitory potency for 5-lipoxygenase and for α-D-glucosidase respectively; they serve as lead compounds for new drugs. © 1990.