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4-Quinolone is an 
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
derived from quinoline
Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only sli ...
. 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.
Synthesis
Thechemical synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In moder ...
of quinolones often involves ring-closing reactions.{{cite journal, title=Co(III)-Catalyzed Enaminone-Directed C-H Amidation for Quinolone Synthesis, author=Shi, Pengfei, author2=Wang, Lili, author3=Chen, Kehao, author4=Wang, Jie, author5=Zhu, Jin, journal= Organic Letters, year=2017, volume=19, issue=9, pages=2418–2421, pmid=28425721, doi=10.1021/acs.orglett.7b00968 Such reactions often install a hydroxyl group (an –OH functional group
In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...
) on the carbon across from the ring nitrogen (i.e., the C-4 positions). An example of such a synthesis is the Camps cyclization
The Camps quinoline synthesis (also known as the Camps cyclization) is a chemical reaction whereby an o-acylaminoacetophenone is transformed into two different hydroxyquinolines (products A and B) using hydroxide ion.
The relative proportions of ...
, 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.
References