Dioncophyllinol D, the First 4-Hydroxylated Naphthylisoquinoline Alkaloid, from the Leaves of Triphyophyllum peltatum

The first isolation of a 4-hydroxylated naphthylisoquinoline alkaloid, dioncophyllinol D (5), from the leaves of Triphyophyllum peltatum (Dioncophyllaceae), is described. Its structural elucidation is based mainly on NMR, degradative, and computational methods. With its rare 7,8'-linkage between the isoquinoline and naphthalene parts, 5 is one of the very few naphthylisoquinolines without a stable configuration at the biaryl axis.