Highly Polar Spiroisoxazolines from the Sponge <i>Aplysina fulva</i>

Abstract

Two new highly polar brominated spiroisoxazolines, araplysillin N9-sulfamate (1) and an N-[5S,10R)-7,9-dibromo-10-hydroxy-8-methoxy-1-oxa-2-azaspiro[4.5]deca-2,6,8-triene-3-carboxy]-4-aminobutanoic acid (2), were isolated from a sample of Aplysina fulva collected in the Florida Keys. The absolute stereostructures of the new compounds were determined from analysis of MS, 1H and 13C NMR, and CD spectroscopy. Compound 2 provides a structural clue that may unify the biosynthesis of brominated spiroisoxazolines.