Longiside, a Novel Digalactosylceramide from the Caribbean Sponge Agelas longissima

Abstract

<jats:title>Abstract</jats:title><jats:p>The Caribbean sponge <jats:italic>Agelas longissima</jats:italic> produces large amounts of (2<jats:italic>S</jats:italic>,3<jats:italic>S</jats:italic>,4<jats:italic>R</jats:italic>)‐<jats:italic>O</jats:italic>‐(β‐<jats:sc>D</jats:sc>‐galactofuranosyl)‐(1→4)‐(α‐<jats:sc>D</jats:sc>‐galactopyranosyl)‐(1→1)‐[(<jats:italic>R</jats:italic>)‐2‐hydroxytetracosylamido]‐1,3,4‐hexadecanetriol (longiside, <jats:bold>1</jats:bold>), a glycosphingolipid with an unprecedented carbohydrate moiety containing a galactose unit in the unusual β‐furanose form. The structure of longiside was determined by spectroscopic analysis and chemical degradation.