2-Quinolone

2-Quinolone is an organic compound related structurally to quinoline. It is the majority tautomer in equilibrium with 2-quinolinol. The compound can be classified as a cyclic amide, and as such is used as an isostere for peptides and other pharmaceutically inspired targets.^[1][2] The 4-methyl-2-quinolone can be prepared by dehydration of acetoacetanilide.^[3]

2-Quinolone (right) and its tautomer 2-hydroxyquinoline (left)

2-Quinolone

Names
Preferred IUPAC name Quinolin-2(1H)-one
Other names Carbostyril 1,2-Dihydro-2-oxoquinoline 1H-Quinolin-2-one
Identifiers
CAS Number	59-31-4
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16365
ChEMBL	ChEMBLCHEMBL186422
ChemSpider	5816
ECHA InfoCard	100.000.382
EC Number	200-420-6
KEGG	C06338
PubChem CID	6038
UNII	803BHY7QWU
CompTox Dashboard (EPA)	DTXSID1058769
InChI InChI=1S/C9H7NO/c11-9-6-5-7-3-1-2-4-8(7)10-9/h1-6H,(H,10,11) Key: LISFMEBWQUVKPJ-UHFFFAOYSA-N
SMILES C1=CC=C2C(=C1)C=CC(=O)N2
Properties
Chemical formula	C9H7NO
Molar mass	145.161 g·mol−1
Appearance	solid
Melting point	199.5 °C (391.1 °F; 472.6 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The isomer 4-quinolone is the parent of a large class of antibiotics called quinolone antibiotics. A prominent example is ciprofloxacin, a broad spectrum antibiotic commonly used for treatment of various infections such as urinary tract infections (UTIs), typhoid, meningitis, gonorrhoea, syphilis,^[4] and skin infections.^[5]