Rotundifolone C10H1402, the principal component of the essential oil obtained from Japanese Mentha rotundifolia, has been found to be 1-methyl-4-isopropylidene-1, 2-epoxy-cyclohexanone-3, which was reduced and rearranged to diosphenol. It is a noteworthy fact that the new ketone seems to be one of the intermediates between carvone series and menthone series.
