Isolation, X-ray crystallography, and computational studies of calydaphninone, a new alkaloid from Daphniphyllum calycillum.
ABSTRACT [structure: see text]. A new hexacyclic alkaloid, calydaphninone (1), containing a 4-azatricyclo[188.8.131.52(1,4)]undecan ring system, has been isolated from the leaves and twigs of Daphniphyllum calycillum (Daphniphyllaceae). Its structure was elucidated by spectral and crystallographic means. Furthermore, conformations of calydaphninone (1) in solution are discussed on the basis of NMR spectral analysis and computational (B3LYP/6-31G*) results.