NEW MATERIAL:The compound of formula I (R is group of formula II or formula III). USE:An antitumor agent. PREPARATION:For example, an ascidian (Cystodytes dellichiajei) collected in a sea area near the Kerama Islands, Okinawa Prefecture, Japan is disintegrated, homogenized and extracted with a (3:1) mixed solvent of methanol and toluene. The extracted liquid is mixed with 1M of saline water, an organic layer is separated and concentrated to dryness under reduced pressure and the residue is dissolved in a small amount of chloroform and passed through a silica gel column. The eluted fraction is subjected to gel-filtration and the eluted fraction of the gel-filtration process is purified by repeating silica gel treatment and gel-filtration treatment to obtain the objective compound of formula I.
展开▼
