5-methyl-3-oxo-tetrahydro-thiophene-2-carboxylic acid methyl ester 、
3,5-二羟基戊苯 以to produce 1,2-dihydro-9-hydroxy-2-methyl-7-n-pentyl-4-oxo-4H-thieno[2,3-c][1] benzopyran, m.p. 188°-190°C的产率得到1,2-dihydro-9-hydroxy-2-methyl-7-n-pentyl-4-oxo-4H-thieno-[2,3-c][1]benzopyran