Pyrylium salt

The pyrylium cation is a six-membered, unsaturated, mono-cyclic compound. Consisting of five carbon atoms and one positively charged oxygen atom, it is a heterocyclic compound, resembling benzene with one substitution in the ring. Like benzene, it is aromatic, and a conjugated system. Having three bonds on its positively charged oxygen atom, pyrylium is an oxonium ion.Benzopyrylium chloride (chromenylium chloride), a salt with chloride as the counterionFlavylium cationNaphthoxanthenium cation The pyrylium cation is a six-membered, unsaturated, mono-cyclic compound. Consisting of five carbon atoms and one positively charged oxygen atom, it is a heterocyclic compound, resembling benzene with one substitution in the ring. Like benzene, it is aromatic, and a conjugated system. Having three bonds on its positively charged oxygen atom, pyrylium is an oxonium ion. A pyrylium salt is a salt containing a pyrylium cation or a derivative cation. Like other oxonium ions, pyrylium is unstable in neutral water. However, pyrylium is much less reactive than ordinary oxonium ions because of aromatic stabilization. Pyrylium cations react with nucleophiles in the 2, 4, and 6 positions, which can induce ring-opening reactions. The high electronegativity of the oxygen results in the strongest single perturbation by one heteroatom in a six-membered ring.