<unk>  (CC) is a secondary metabolite of the fungus Penicillium islandicum that causes hepatic necrosis and has carcinogenic properties.  It is listed as an IARC Group 3 carcinogen.
Chemically, it is a chlorinated macrocyclic pentapeptide derived from the amino acids 3-phenyl-β-alanine, serine, dichloroproline, and aminobutyric acid.
Cyclochlorotine
Acetylene tetrabromide
Nitrazine
N-Nitrosonornicotine
Triphenylmethane
Trichloroethylene
4-Methylmethcathinone
Tetrachloroethylene