Isolation and Characterization of 1,3-Dimethylisoguanine from the Bermudian Sponge Amphimedon viridis

Abstract
The new compound 1,3-dimethylisoguanine has been isolated and characterized from the Bermudian sponge Amphimedon viridis. Chemical conversion of the natural product to theophylline and 2D NMR methods were used to determine the position of the methyl groups on the purine ring. Analysis of the mass spectral fragmentation pattern allowed assignment of the purine ring as isoguanine.