Xantocillin
{{chembox
| ImageFile =Xantocillin.svg
| ImageSize =250
| ImageFile1 =Xantocillin-from-xtal-3D-balls.png
| ImageFile2 =Xantocillin-from-xtal-3D-vdW.png
| PIN =4,4′-[(1Z,3Z)-2,3-Diisocyanobuta-1,3-diene-1,4-diyl]diphenol
| OtherNames =Xanthocillin X, Ophthocillin
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo =580-74-5
| PubChem =5378293
| ChemSpiderID =21106491
| ChEMBL = 1977264
| SMILES =[C-]#[N+]C(=CC1=CC=C(C=C1)O)C(=CC2=CC=C(C=C2)O)[N+]#[C-]
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 06Z55VZ40D
}}
|Section2={{Chembox Properties
| C =18 |H=12 |N=2 |O=2
| Appearance =Yellow crystals
| Density =
| MeltingPtC = 200
| MeltingPt_notes = (decomposes)
| BoilingPt =
| Solubility =
}}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}
Xantocillin{{Cite web |last=PubChem |title=Xantocillin |url=https://pubchem.ncbi.nlm.nih.gov/compound/5378293 |access-date=2023-11-03 |website=pubchem.ncbi.nlm.nih.gov |language=en}} (INN), also known as xanthocillin X or ophthocillin, was the first reported natural product found to contain the isocyanide functional group. It was first isolated from Penicillium notatum by Rothe in 1950{{cite journal
| author = W. ROTHE
| title =Vorläufige Mitteilung über eine neues Antibiotikum
| journal = Pharmazie
| volume = 5
| year = 1950
| pages = 190
}} and subsequently from several other sources.{{cite journal
| author = Paul J. Scheuer
| title = Isocyanides and cyanides as natural products
| journal = Accounts of Chemical Research
| volume = 25
| year = 1992
| issue = 10
| pages = 433–439
| doi = 10.1021/ar00022a001