The structures of four new himbacine-like Galbulimima alkaloids

Abstract

The structures of four new alkaloids isolated from the bark of the rain forest trees Galbulimima belgraveana and Galbulimima baccata have been determined by a combination of NMR spectra and single crystal X-ray crystallography. Two of the alkaloids are simple oxygenated derivatives of himbacine, while the remaining two are based on a novel 7,19-cyclo-himbacine skeleton.