Methyl iodide → 7-Hydroxy-5-methoxy-4-methyl-2H-1-benzopyran-2-one

Participants

Reaction Steps

The 4-methyl-5,7-diacetoxycoumarin (XXXIV) was dissolved in dimethoxyethane (80 ml) and a solution of dry K2CO3 (6.6 g) and methyl iodide (3 ml) was added. The mixture was refluxed for 6 h, the solvent was evaporated and the residue, after addition of water:methanol (50:50; 80 ml), was heated to reflux 20 min. By evaporation of the MeOH under reduced pressure and by cooling a precipitate was formed, which by crystallization of first from MeOH and then from Me2CO gave 4-methyl-5-methoxy-7-hydroxycoumarin (XXXV; 1.52 g; m.p. 261°-3° C.). ##STR38##

Provenance & Evidence