Pyridine Nucleosides Neopetrosides A and B from a Marine Neopetrosia sp. Sponge. Synthesis of Neopetroside A and Its β-Riboside Analogue

Neopetrosides A (1) and B (2), new naturally occurring ribosides of nicotinic acid with extremely rare α-N-glycoside linkages and residues of p-hydroxybenzoic and pyrrole-2-carboxylic acids attached to C-5', were isolated from a marine Neopetrosia sp. sponge. Structures 1 and 2 were determined by NMR and MS methods and confirmed by the synthesis of 1 and its β-riboside analogue (3). Neopetroside A (1) upregulates mitochondrial functions in cardiomyocytes.