Computational study of naphthylisoquinoline alkaloids with antimalarial activity from Dioncophyllaceae and Ancistrodaceae in vacuo

Abstract

This study investigates 33 naphthylisoquinoline alkaloids with antimalarial activity isolated from different tropical plants belonging to the Dioncophyllaceae and Ancistrodaceae families. All these molecules have two moieties, a naphthalene moiety and an isoquinoline moiety. A thorough conformational study was carried in vacuo at two levels of theory, HF/6-31G(d,p) and DFT/B3LYP/6-31+G(d,p). Frequency calculations were also performed in vacuo for all the calculated conformers, at both levels of theory. The major stabilizing factors are the intramolecular hydrogen bonds. The mutual orientation of the two moieties also has considerable influence, with marked preference for the naphthalene moiety to be perpendicular to the isoquinoline moiety.