Rotundifolone, a new terpenic ketone, C10H14O2 has been isolated from the essential oil of M. rotundifolia in Japan. This ketone is highly dextro-rotatory, and has a low melting point 27.5° The wave lengths of the ultraviolet absorption maxima of rotundifolone and its semicarbazone are 260mμ (log ε=3.95) and 273mμ (log ε=4.12) respectively. This indicates that rotundifolone has an α, β-unsaturated carbonylic system.
