Caldaphnidines A–F, six new Daphniphyllum alkaloids from Daphniphyllum calycinum

Six new Daphniphyllum alkaloids, namely caldaphnidines A–F (), together with eight known ones, deoxycalyciphylline B, deoxyisocalyciphylline B, bukittiggine, calycicine A, methyl homosecodaphniphyllate, daphnilactone B, and daphnezomines L–M, were isolated from the leaves and the seeds of Daphniphyllum calycinum. The structure of was determined by a single-crystal X-ray diffraction study, and the structures of were established by spectral methods, especially two-dimensional NMR techniques (1H–1H COSY, HMQC, HMBC, and NOESY).