Aristolane-type Sesquiterpenoids from Nardostachys chinensis and Revised Structure of Aristolanhydride.

Four hitherto unknown aristolane-type sesquiterpenes, including one novel 8,9-secoaristolane, namely secoaristolenedioic acid (1), two aristolone derivatives, namely 1α,2β-dihydroxyaristolone (2), 9-epidebilon (3), and one rare aristolane-chalcone hybrid, namely 3'-hydroxynardoaristolone A (4) were isolated from the ethanol extract of the roots and rhizomes of Nardostachys chinensis. Their structures were elucidated on the basis of extensive spectroscopic analysis. In addition, the structure of aristolanhydride, recently isolated from the same species, was corrected by reanalysis of the published NMR data.

Pterocarpadiols A-D, Rare 6a,11b-Dihydroxypterocarpans from Derris robusta.

Four hitherto unknown 6a,11b-dihydroxypterocarpans, namely pterocarpadiols A-D (1-4), were isolated from the ethanol extract of the twigs and leaves of Derris robusta. Their structures were elucidated on the basis of extensive spectroscopic analysis. Pterocarpadiols A-D are a kind of very rare 6a,11b-dihydroxypterocarpans, and their presence as markers may be helpful in chemotaxonomical classification.

Hybridaphniphyllines A and B, Daphniphyllum alkaloid and iridoid hybrids suggestive of Diels-Alder cycloaddition in Daphniphyllum longeracemosum.

Two Daphniphyllum alkaloid and iridoid hybrids with the hitherto unknown decacyclic fused skeletons, hybridaphniphyllines A and B, along with one diamino Daphniphyllum alkaloid, daphnicyclidin I, were isolated from dried stems and leaves of Daphniphyllum longeracemosum. Their structures were elucidated on the basis of extensive spectroscopic analysis, and the absolute configuration of daphnicyclidin I was deduced by the CD exciton chirality method. A biogenetic pathway for 1 and 2 involving natural Diels-Alder cycloaddition is proposed.