Calycinumines A and B, two novel alkaloids from Daphniphyllum calycinum.

Two novel alkaloids, calycinumines A (1) and B (2), were isolated from the twigs of Daphniphyllum calycinum. Calycinumine A (1) is the first example of C-22-nor yuzurimine-type alkaloids, and calycinumine B (2) features an unprecedented heteroatom-containing adamantane-like western hemisphere of the alkaloid. Their structures were elucidated by spectroscopic methods, and that of 1 was confirmed by a single-crystal X-ray diffraction.