3, 5-Pyridyne (3) has been generated by flash vacuum pyrolysis of 3, 5-diiodopyridine (20) and 3, 5-dinitropyridine (21) and characterized by IR spectroscopy in cryogenic argon matrices. The aryne can clearly be distinguished from other side products by its photolability at 254 nm, inducing a rapid ring-opening presumably to (Z)-1-aza-hex-3-ene-1, 5-diyne. As byproducts of the pyrolysis, HCN and butadiyne were identified, together with traces of ...
