Diketopiperazines and Phthalides from a Marine Derived Fungus of the Order Pleosporales

Five metabolites, ( Z)-6-benzylidene-3-hydroxymethyl-1,4-dimethyl-3-methylsulfanylpiperazine-2,5-dione ( 1), (3S,3'R)-3-(3'-hydroxybutyl)-7-methoxyphthalide ( 2), ( S)-3-butyl-7-methoxyphthalide ( 3), (3R,6R)-bisdethiodi(methylthio)hyalodendrin ( 4), and bis- N-norgliovictin ( 5), were isolated from the culture broth of the marine derived fungus of the order Pleosporales strain CRIF2. Compounds 1 and 2 are new fungal metabolites, while 3 was isolated for the first time as a natural product. Compounds 1, 3, and 4 exhibited only weak cytotoxic activity, while 5 was inactive at 50 microg/mL.