Chemical constituents from a Thai tunicate, Didemnum sp.

Abstract

Four halogenated pyrrolo[2,3-d]pyrimidine nucleosides were isolated from a Thai tunicate, Didemnum sp.: including three known compounds, 4-amino-7-(5'-deoxyribos-1'beta-yl)-5-iodopyrrolo[2,3-d]pyrimidine, 4-amino-7-(5'-deoxyribos-1'beta-yl)-5-bromopyrrolo[2,3-d]pyrimidine, and 4-amino-7-(5'-deoxyxylos-1'beta-yl)-5-iodo-pyrrolo[2,3-d]pyrimidine and a new derivative, 4-amino-7-(5'-deoxyxylos-1'beta-yl)-5-bromopyrrolo[2,3-d]pyrimidine. The structures and relative stereochemistry of the compounds were elucidated through extensive analyses of their uv, ir, ms, 1H and 13C nmr spectral data, especially NOE and LCMS techniques, as well as comparison with the data of related compounds.