Chemistry of Renieramycins. Isolation and Structure of Stabilized Renieramycin Type Derivatives from Thai Sponge, Xestospongia sp. with Chemical Transformations

Abstract

In connection with our search for new metabolites via isolation and characterization of biologically active compounds from Thai marine animals, we found a blue sponge, Xestospogia sp. growing around Sichang Island in the Gulf of Thailand. We present the isolation and structure elucidation of renieramycins M–O, and Q–S, pretreated with potassium cyanide in methanolic buffer solution. Renieramycin E, prepared by treating renieramycin M with silver nitrate in aqueous acetonitrile was transformed into simple isoquinoline quinones, such as mimosamycin and renierone by treatment with a catalytic amount of TFA in chloroform. This strategy is the first example of the gram-scale preparation of this series of compounds, and presents a potential solution for increasing the gram-scale supply of novel natural products from marine sources.