Chemistry:Quinolizinium

Quinolizinium

Names
Other names pyrido[1,2-a]pyridinium
Identifiers
CAS Number	255-59-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1423269
ChEBI	CHEBI:36646
ChemSpider	107593
PubChem CID	120516
InChI InChI=1S/C9H8N/c1-3-7-10-8-4-2-6-9(10)5-1/h1-8H/q+1 Key: GUOHRXPYGSKUGT-UHFFFAOYSA-N
SMILES C1=CC=[N+]2C=CC=CC2=C1
Properties
Chemical formula	C 9H 8N+
Appearance	colorless
Related compounds
Related compounds	4H-Quinolizine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tracking categories (test):

• SizeSet

Quinolizinium refers to the heterocyclic cation with the formula C
9H
8N+
. The cation is isoelectronic and nearly isostructural with naphthalene, the difference being the replacement of one of the two carbons at the fusion positions with N⁺. The parent quinolizine has not been isolated but salts of these aromatic quinolizinium compounds are well known. Several syntheses begin with 2-substituted pyridines and involve N-alkylation and various dehydrogenation reactions. The quinolizinium core is represented in the berberine family of natural products. It is formally derived from the elusive quinolizines by hydrde abstraction. According to X-ray crystallography of the hexafluorophosphate salt, which is colorless, C
9H
8N+
is planar.

Reactions

Being a cation, quinolinizium resists electrophilic attack, although it can be brominated. Catalytic hydrogenation gives quinolizidine.