Caldaphnidines a-f, six new Daphniphyllum alkaloids from Daphniphyllum calycinum

Six new Daphniphyllum alkaloids, namely caldaphnidines A-F (1-6), 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 I was determined by a single-crystal X-ray diffraction study, and the structures of 2-6 were established by spectral methods, especially two-dimensional NMR techniques (H-1-H-1 COSY, HMQC, HMBC, and NOESY). (c) 2005 Elsevier Ltd. All rights reserved.