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

Six new Daphniphyllum alkaloids, namely caldaphnidines A-F (1-6), were isolated from the leaves and the seeds of Daphniphyllum calycinum. The structure of 1 was determined by a single-crystal X-ray diffraction, and the structure of 2-6 was established by spectroscopic methods, especially 2D NMR techniques (1H-1H COSY, HMQC, HMBC, and NOESY).