Method of preparing furocoumarins

Abstract From the Canadian patent

Pharmacologically valuable furocoumarins of the general formula, (I), wherein R is selected from the group consisting of hydrogen a, hydroxyl group and a lower alkoxy group are prepared by reacting, a substituted coumarin of the general formula (II), wherein R has the aforesaid meaning or an alkali metal salt, thereof, with a haloacetale of the general formula (III), wherein R1 is a lower alkyl group and Hal is selected from the group consisting of chlorine and bromine in an inert, non-, aqueous organic solvent or solvent mixture to obtain an, intermediate product of the general formula (IV), wherein R and R1 have the aforesaid meanings which is treated, with a dilute acid at an elevated …