Syntheses of Unsaturated Lactones

Part II. Flavorous Nature of Some 4- and 5-Substituted-5-Hydroxy-2-Enoic Acid Lactones

Abstract

Homologous 4- and 5-substituted 5-hydroxy-2-enoic acid lactone were prepared, and the nature of their flavors as a butter cake flavor was investigated. Among those, unsaturated lactones having the best flavorous nature have the following structural properties. The length of a substituted residue at the γ-position of the lactone ring should be a short as possible. The lactones have a n-amyl residue at the δ-positio, and the total carbon number of a compound is ten. Namely, a compound is so better as to have a structure similar to that of 5-hydroxy-2-decenoic acid lactone.