Amotin and amoenin,two sesquiterpenes of the picrotoxane group from Dendrobium amoenum

Two new sesquiterpenes, amotin and amoenin, of the picrotoxane group were isolated from Dendrobium amoenum. The constitution of amoenin was evident from spectral investigations and by its conversion into α-dihydro-picrotoxinin on oxidation with oxygen in the presence of platinum. The constitution of amotin was shown by its spectral properties and the conversion of aduncin into amotin by hydrogenolysis of its epoxide ring. That the configuration at C-4 in aduncin and amotin is R was supported by circular dichroism measurements on some derivatives of picrotoxinin and aduncin.