Acetic Acid → 6-Acetyl-2,3,-dihydro-7-methoxy-4-methyl-4H-1-benzopyran

Participants

Reaction Steps

The methyl ether of step (c) (58.0 g) was dissolved in dry benzene (1 l) and glacial acetic acid (22.3 ml) was added. Boron trifluoride gas was bubbled through the reaction mixture for 1 hour and then stirring was continued overnight. The reaction mixture was poured into water, the organic layer was separated and the aqueous phase was extracted with more ether. The organic extracts were washed with sodium bicarbonate solution, then water, and dried. Evaporation gave 67.8 g of the desired product (95%). MS and NMR analysis were correct for the required compound.

Provenance & Evidence