. . . "The process of claim 4, wherein heating is carried out in a solvent in the presence of a hydrogen halide acceptor and is continued until production of an ??-loweralkylfurocoumarin of the formula ##STR3## in which R, R1, and R2 are selected from the group consisting of hydrogen, alkyl, and lower-alkoxy; R4 in both the starting material and product is other than hydrogen; and R5 and R6 are hydrogen" . .