4-Quinolone

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4-Quinolone
4-Quinolone.svg
Names
Preferred IUPAC name
Quinolin-4(1H)-one
Other names
1H-Quinolin-4-one
Identifiers
3D model (JSmol)
ChEBI
ECHA InfoCard 100.009.336 Edit this at Wikidata
EC Number
  • 210-268-2
UNII
  • InChI=1S/C9H7NO/c11-9-5-6-10-8-4-2-1-3-7(8)9/h1-6H,(H,10,11)
    Key: PMZDQRJGMBOQBF-UHFFFAOYSA-N
  • C1=CC=C2C(=C1)C(=O)C=CN2
Properties
C9H7NO
Molar mass 145.161 g·mol−1
Melting point 208–210 °C (406–410 °F; 481–483 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

4-Quinolone is an organic compound derived from quinoline. It and 2-quinolone are the two most important parent (meaning simplified) quinolones. 4-Quinolone exists in equilibrium with a minor tautomer, 4-hydroxyquinoline (CAS#611-36-9). Aside from pedagogical interest, 4-quinolone is of little intrinsic value but its derivatives, the 4-quinolone antibiotics, represent a large class of important drugs.[1]

The tautomeric equilibrium relating 4-quinolone (right) and 4-hydroxyquinoline (left)

Synthesis[edit]

The chemical synthesis of quinolones often involves ring-closing reactions.[2] Such reactions often install a hydroxyl group (an –OH functional group) on the carbon across from the ring nitrogen (i.e., the C-4 positions). An example of such a synthesis is the Camps cyclization, which, depending on starting materials and reaction conditions, can give both 2-hydroxyquinolines (B) and 4-hydroxyquinolines (A) as shown. The hydroxyquinolines tautomerize to the quinolones.

The Camps cyclization, a quinoline synthesis giving 2- and 4-hydroxyquinolines.

References[edit]

  1. ^ Andriole, VT The Quinolones. Academic Press, 1989.
  2. ^ Shi, Pengfei; Wang, Lili; Chen, Kehao; Wang, Jie; Zhu, Jin (2017). "Co(III)-Catalyzed Enaminone-Directed C-H Amidation for Quinolone Synthesis". Organic Letters. 19 (9): 2418–2421. doi:10.1021/acs.orglett.7b00968. PMID 28425721.