Hybrid Pyrrole–Imidazole Alkaloids from the Sponge Agelas sceptrum
journal contributionposted on 12.02.2016, 00:00 by Julie Muñoz, Matthias Köck
A chemical investigation of the tropical sponge Agelas sceptrum from Plana Cays (Bahamas) led to the isolation of two hybrid pyrrole–imidazole alkaloids (PIAs), 15′-oxoadenosceptrin (1) and decarboxyagelamadin C (2). Herein, we report their challenging structure elucidation established by NMR and ECD spectroscopy. 15′-Oxoadenosceptrin (1) shows sceptrin merged with an adenine moiety, not yet encountered in the PIA family, whereas decarboxyagelamadin C (2) is a close derivative of agelamadins C to E recently isolated from an Agelas sp. from Okinawa.