Hydroxybenzoquinones from Myrsinaceae Plants. I. Reconfirmation of the Structure of Maesaquinoes and Isolation of Acetylmaesaquinone from Maesa japonica MORITZI

The structure (IIa) of maesaquinone, a benzoquinone from Maesa japonica MORITZI, proposed by Hiramoto, ^<5,6)> was further confirmed by spectral evidences, gas chromatography of the oxidation products, and an improved synthesis of the dihydro derivative (IIb). Isolation of monoacetate (VIIa) of IIa from the fruits suggested that VIIa is the chief component of the fruits.