Cystodytin L, a Pyridoacridine Alkaloid from the Senegalese Tunicate Cystodytes sp.

Abstract

Chemical investigation of the brown-colored tunicate Cystodytes sp. yielded six pyridoacridine alkaloids, including the known metabolites arnoamine C (1), styelsamine C (2), cystodytin B (3), E (4) and G (5) and the new compound, cystodytin L (6). Their chemical structures were established on the basis of combination of [α]_D, physical and spectroscopic methods 1D and 2D NMR, in addition to mass spectrometry and comparison with literature data. The absolute configuration of C-12 in compounds 4-6 was identified as R by electronic circular dichroism (ECD) spectroscopy coupled with time-dependent density functional theory calculations.