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 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 210-268-2
PubChem CID
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) 4-QuinoloneEquilibrium.png
The tautomeric equilibrium relating 4-quinolone (right) and 4-hydroxyquinoline (left)

Synthesis

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. Camps Quinoline Synthesis Scheme.png
The Camps cyclization, a quinoline synthesis giving 2- and 4-hydroxyquinolines.

Related Research Articles

Organic chemistry Subdiscipline of chemistry, with especial focus on carbon compounds

Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon-carbon covalent bonds. Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical study.

Quinoline Chemical compound

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 slightly soluble in cold water but dissolves readily in hot water and most organic solvents. Quinoline itself has few applications, but many of its derivatives are useful in diverse applications. A prominent example is quinine, an alkaloid found in plants. Over 200 biologically active quinoline and quinazoline alkaloids are identified. 4-Hydroxy-2-alkylquinolines (HAQs) are involved in antibiotic resistance.

Enols, or more formally, alkenols, are a type of reactive structure or intermediate in organic chemistry that is represented as an alkene (olefin) with a hydroxyl group attached to one end of the alkene double bond. The terms enol and alkenol are portmanteaus deriving from "-ene"/"alkene" and the "-ol" suffix indicating the hydroxyl group of alcohols, dropping the terminal "-e" of the first term. Generation of enols often involves removal of a hydrogen adjacent (α-) to the carbonyl group—i.e., deprotonation, its removal as a proton, H+. When this proton is not returned at the end of the stepwise process, the result is an anion termed an enolate (see images at right). The enolate structures shown are schematic; a more modern representation considers the molecular orbitals that are formed and occupied by electrons in the enolate. Similarly, generation of the enol often is accompanied by "trapping" or masking of the hydroxy group as an ether, such as a silyl enol ether.

Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen; the term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular formula C3H3NS. The thiazole ring is notable as a component of the vitamin thiamine (B1).

The Robinson annulation is a chemical reaction used in organic chemistry for ring formation. It was discovered by Robert Robinson in 1935 as a method to create a six membered ring by forming three new carbon–carbon bonds. The method uses a ketone and a methyl vinyl ketone to form an α,β-unsaturated ketone in a cyclohexane ring by a Michael addition followed by an aldol condensation. This procedure is one of the key methods to form fused ring systems.

Enolate Organic anions derived from the deprotonation of carbonyl compounds

Enolates are organic anions derived from the deprotonation of carbonyl compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds.

Tropinone Chemical compound

Tropinone is an alkaloid, famously synthesised in 1917 by Robert Robinson as a synthetic precursor to atropine, a scarce commodity during World War I. Tropinone and the alkaloids cocaine and atropine all share the same tropane core structure. Its corresponding conjugate acid at pH 7.3 major species is known as tropiniumone.

One-pot synthesis

In chemistry a one-pot synthesis is a strategy to improve the efficiency of a chemical reaction whereby a reactant is subjected to successive chemical reactions in just one reactor. This is much desired by chemists because avoiding a lengthy separation process and purification of the intermediate chemical compounds can save time and resources while increasing chemical yield.

Camps quinoline synthesis

The Camps quinoline synthesis is a chemical reaction whereby an o-acylaminoacetophenone is transformed into two different hydroxyquinolines using hydroxide ion.

Organoboron chemistry

Organoborane or organoboron compounds are chemical compounds of boron and carbon that are organic derivatives of BH3, for example trialkyl boranes. Organoboron chemistry or organoborane chemistry is the chemistry of these compounds.

In the Ullmann condensation or Ullmann-type reaction is the copper-promoted conversion of aryl halides to aryl ethers, aryl thioethers, aryl nitriles, and aryl amines. These reactions are examples of cross-coupling reactions.

In chemistry, hydroboration refers to the addition of a hydrogen-boron bond to C-C, C-N, and C-O double bonds, as well as C-C triple bonds. This chemical reaction is useful in the organic synthesis of organic compounds. The development of this technology and the underlying concepts were recognized by the Nobel Prize in Chemistry to Herbert C. Brown. He shared the Nobel prize in chemistry with Georg Wittig in 1979 for his pioneering research on organoboranes as important synthetic intermediates.

The Niementowski quinoline synthesis is the chemical reaction of anthranilic acids and ketones to form γ-hydroxyquinoline derivatives.

Cyclopropanation

Cyclopropanation refers to any chemical process which generates cyclopropane rings. It is an important process in modern chemistry as many useful compounds bear this motif; for example pyrethroids and a number of quinolone antibiotics. However the high ring strain present in cyclopropanes makes them challenging to produce and generally requires the use of highly reactive species, such as carbenes, ylids and carbanions. Many of the reactions proceed in a cheletropic manner.

The Conrad–Limpach synthesis is the condensation of anilines (1) with β-ketoesters (2) to form 4-hydroxyquinolines (4) via a Schiff base (3). The overall reaction type is a combination of both an addition reaction as well as a rearrangement reaction. This reaction was discovered by Max Conrad (1848–1920) and Leonhard Limpach (1852–1933) in 1887 while they were studying the synthesis of quinoline derivatives.

8-Hydroxyquinoline Chemical compound

8-Hydroxyquinoline is a chelating agent which has been used for the quantitative determination of metal ions.

Tris(8-hydroxyquinolinato)aluminium Chemical compound

Tris(8-hydroxyquinolinato)aluminium is the chemical compound with the formula Al(C9H6NO)3. Widely abbreviated Alq3, it is a coordination complex wherein aluminium is bonded in a bidentate manner to the conjugate base of three 8-hydroxyquinoline ligands.

Knorr quinoline synthesis

The Knorr quinoline synthesis is an intramolecular organic reaction converting a β-ketoanilide to a 2-hydroxyquinoline using sulfuric acid. This reaction was first described by Ludwig Knorr (1859–1921) in 1886

Rosoxacin

Rosoxacin is a quinolone antibiotic indicated for the treatment of urinary tract infections and certain sexually transmitted diseases. Rosoxacin is not available in the United States.

Gould–Jacobs reaction

The Gould–Jacobs reaction is an organic synthesis for the preparation of quinolines and 4‐hydroxyquinoline derivatives. The Gould-Jacobs reaction is a series of reactions. The series of reactions begins with the condensation/substitution of an aniline with alkoxy methylenemalonic ester or acyl malonic ester, producing anilidomethylenemalonic ester. Then through a 6 electron cyclization process, 4-hydroxy-3-carboalkoxyquinoline is formed, which exist mostly in the 4-oxo form. Saponification results in the formation of an acid. This step is followed by decarboxylation to give 4-hydroxyquinoline. The Gould-Jacobs reaction is effective for anilines with electron‐donating groups at the meta‐position.

References

  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.