Studies on Phenolic Lactones

Isohibalactone, the geometric isomer of hibalactone, was synthesized by the following route. Piperonylsuccinic acid anhydride was converted into thioethyl methyl ester ans was reduced to piperonylbutyrolactone by Raney nickel catalyst. Piperonylbutyrolactone was also prepared from piperonylsuccinic anhydride by the reduction with amalgamated aluminum. Condensation of piperdnal with the lactone in the presence of potassium amide afforded α-(3,4-methyIenedioxy-phenyl-hydroxymethyl)-β-(3,4-methylenedioxybenzyl)-butyrolactone, m.p. 151~2°C. Dehydration of the hydroxylactone with p-toluenesulfonic acid gave isohibalactone, m.p. 156~6.5°C.