[Synthesis and antiulcer effects of 5-hydroxy-4-[2-substituted-(E)-ethenyl]-2(5H)-furanone. (1)].

gamma-Hydroxybutenolides possessing conjugated substituents at the beta-position and their related compounds have been synthesized by the previously reported procedure with minor modifications and their antiulcer activities have been examined in the HCl-ethanol induced ulcer model often used for the evaluation of gastric mucosal protective factor enhancing effect. The compound A-1 5-hydroxy-4-[2-(2,6,6-trimethyl-1-cycohexenyl-1-yl)-(E)-ethenyl]-2 (5H)-furanone showed a pronounced effect at a low dosage of 5 mg/kg p.o. and some analogues compounds also exhibited potent inhibitory activity as compared with the reference drugs. The relationship between the structure of gamma-hydroxybutenolides and the antiulcer effect has been also examined and then the 5-hydroxyl group has been found to be essentially functional one to have antiulcer activity.