Tetillapyrone and nortetillapyrone, two unusual hydroxypyran-2-ones from the marine sponge Tetilla japonica.

Extraction of the marine sponge Tetilla japonica from the Bay of Thailand furnished tetillapyrone and nortetillapyrone, two unusual tetrahydrofurylhydroxypyran-2-ones, whose structures were established by NMR spectrometry and an X-ray analysis of tetillapyrone.