PHORBAZOLES A-D, NOVEL CHLORINATED PHENYLPYRROLYLOXAZOLES FROM THE MARINE SPONGE PHORBAS AFF CLATHRATA

Four new chlorinated phenylpyrrolyloxazoles, phorbazoles A-D (1a-4) ha ve been isolated from the sponge Phorbas aff clathrata. The structure of phorbazole A was unambiguously determined by X-ray diffraction stud ies of its dimethyl derivative (Ib). The structures of compounds 2-4 w ere determined by extensive use of 1D and 2D NMR techniques. Phorbazol es A-D represent a new class of marine alkaloids embodying the previou sly unprecedented, chlorinated pyrrole moiety, from marine sources.