Abstract: The structure of the tetraene antifungal antibiotic tetrin B has been assigned as 2. Evidence presented includes the reduction of tetrin B to the saturated hydrocarbon 3, 15- dimethylhexacosane (3) and its basic hydrolysis to 12-methyl-13- hydroxytetradecapentaenal (4). Nmr and mass spectra are also fundamental in the structural assignment. etrin, an antifungal antibiotic belonging to the class T containing an isolated ...