Natural pungent compounds. III. The paradols and associated compounds

Abstract

A new series of pungent compounds, the 1-(4'-hydroxy-3'-methoxyphenyl). alkan-3-ones, has been isolated from grains of paradise (Amomum melegueta Roscoe) and detected in ginger (Zingiber officinale Roscoe). The name, paradol, which has been previously applied to a mixture of these compounds and the gingerols, is suggested as a group name prefixed with a number corresponding to that given to the gingerol with the same side-chain length to distinguish individual members. The structure of [6]-paradol, as suggested by spectroscopic techniques, was confirmed by synthesis from [6]-gingerol. It occurred in grains of paradise in quantities up to 1.5% and was accompanied by (+)-[6]- gingerol in almost equal amounts. Trace quantities of [8]-gingerol, [a]-paradol, and [6]-shogaol were also present.