Allyl bromide → 2H-1-Benzopyran-2-one, 4,8-dimethyl-7-(2-propen-1-yloxy)-

Participants

Reaction Steps

7-Hydroxy-4,8-dimethylcoumarin (91.075 g, 0.479 mol), anhydrous K2CO3 (302.9 g, 2.190 mol), and allyl bromide (217.1 mL, 2.51 mol) were added to 2.5 L of reagent grade acetone. The milky mixture was refluxed for eight hours with overhead stirring, filtered, and the filtrate was concentrated to dryness with the rotary evaporator to obtain 7-allyloxy-4,8-dimethylcoumarin (113.5 g, 0.493 mol, 103%). The crude product melted at 94.0°-100° C. (lit. mp 108° C.) and was used in the next step.

Provenance & Evidence