Constituents of the roots of Rubia yunnanensis.

Four new naphthohydroquinones, rubinaphthins A (1), B (2), C (3), and D (4), together with 11 known compounds were isolated and characterized from the roots of Rubia yunnanensis. The structures of 1-4 were elucidated by spectral analysis and chemical transformation.

New pavine N-oxide alkaloids from the stem bark of Cryptocarya chinensis Hemsl.

Three new pavine N-oxide alkaloids, (-)-isocaryachine-N-oxide B, (+)-caryachine-N-oxide, (-)-caryachine-N-oxide, and a new isoquinoline alkaloid, 6,7-methylenedioxy-N-methylisoquinoline together with 11 known alkaloids were isolated and characterized from the stem bark of Cryptocarya chinensis. The structures of the isolated compounds were determined by spectral methods. The stereochemistry of pavine-N-oxide alkaloids is also discussed.