Quinolone chemistry

This coupling works best when the halogen at the 7-position is bromine rather than chlorine or fluorine. This represents the first appUcation of this coupling reaction to the intact quinoline nucleus and thus represents an important advance in quinolone chemistry. 

Petersen U, Schenke T. The chemistry of the quinolones Chemistry in the periphery of the quinolones. In Quinolone Antibacterials. Kuhlmann J, DalhofFA, Zeiler H-J (Eds.) Springer Berlin, Heidelberg, New York, Barcelona, Budapest, Hong Kong, London, Milan, Paris, Santa Clara, Singapore, Tokyo, 1998, pp. 63-118. 

Nosova E, Lipunova G, Charushin V (2007) Fluorine-containing derivatives of condensed quinolines and related systems synthesis and biological activity. In Kartsev V (ed) Selected methods for synthesis and modification of heterocycles. Quinolones chemistry tmd biological activity. ICSPF, Moscow... 

If one employs o-iodoaniline derivatives in this double insertion chemistry, 2-quinolones are generated in good yield after a basic work-up to remove the nitrogen protecting group (Scheme 14).15... 

Further development in the chemistry of oxazolidinone antibacterials was based mainly on the assumption that the 4-pyridyl moiety of one of Dupont s lead compounds, E-3709, might be amenable to replacement by suitably saturated heterocyclic bioisosteres [48]. This assumption was based on an example in which successful replacement of the piperazine ring system in the quinolone antibacterials, such as ciprofloxacin, with a pyridine fragment, such as seen in Win-57273, results in improvement of both the antibacterial and the pharmacokinetic profiles of the compounds. Similarly, as in the case of ciprofloxacin and Win-57273, it was predicted that the presence of a small but highly electron-withdrawing fluorine atom would be tolerated at the meta position(s) of the central phenyl ring, and would confer enhanced antibacterial activity and/or other desirable properties to the targeted oxazolidinones, as shown in Fig. 3. 

Volmer D.A., B. Mansoori, and S.J. Locke (1997). Study of 4-quinolone antibiotics in biological samples by short-column liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Analytical Chemistry 69 4143 155. 

The simplicity and convenience of this chemistry led to an industrial application on a large scale, as illustrated by the synthesis of Danofloxacin, an animal health quinolone antibiotic (equation 107). 

Standard reactions of aliphatic chemistry can be applied for example, chroman (123) can be prepared by ring closure of (122). 4-Quinolones result from the Camps reaction (124 — 125), and flavonone (127) by cyclization of (126). 

Due to a very efficient singlet- to triplet-state intersystem crossing, the [2 + 2]-photocycloaddition chemistry of 2-quinolones can be initiated easily by direct excitation at 300-350 nm [102], The addition of a sensitizer is not required. The parent compound has been first employed in a [2 + 2]-photocycloaddition as early as 1968 [103]. With regard to regio- and stereoselectivity, 2-quinolone (107) behaves as expected, exhibiting a preference for HTproduct formation with electron-rich olefins, such as 1,1-dimethoxyethene (Scheme 6.39, DMA = N,N-dimethylacetamide). The highly efficient reaction delivers product 108 quantitatively [104], The preference for... 

Lewis, F.D., Reddy, G.D., Elbert, J.E., Tillberg, B.E., Meltzer, J.A., and Kojima, M. (1991) Spectroscopy and photochemistry of 2-quinolones and their Lewis acid complexes. Journal of Organic Chemistry, 56, 5311-5318. 

Selig, P. and Bach, T. (2006) Photochemistry of 4-(2 -aminoethyl) quinolones enantioselective synthesis of tetracyclic tetrahydro-laH-pyrido [4, 3 2,3]-cydobuta[l,2-c] quinoline-2,11 (3H, 8H)-diones by intra- and inter-molecular [2 + 2] photocydoaddition reactions in solution. Journal of Organic Chemistry, 71, 5662—5673. 

The quinolone class of antibiotics has been investigated by many research teams in the past, and numerous reviews have reported on the chemistry [31,32,47-56], structure-activity relationships [56-66], and mode of action [7,8,56,65,67] of this class of compounds. 

Grohe K. The chemistry of the quinolones Methods of synthesizing the quinolone ring system. In Quinolone Antibacterials. Kuhlmann J, DalhoffA,... 

Bouzard D. Recent advances in the chemistry of quinolones. In Recent Progress in the Chemical Synthesis of Antibiotics. Lukacs G (Ed.) Springer-Verlag, Berlin, Heidelberg, 1990, pp. 249-283. 

From other o-substituted benzenes. Standard reactions of aliphatic chemistry can be applied for example, chroman 102 can be prepared by ring closure of 101. 4-Quinolones result from the Camps reaction (103 104), and flavonone 106 is prepared by cyclization of 105. The nucleophile-induced cyclization of suitably substituted 0-alkynylanilines 107 provides a general synthetic approach to quinolines 108 (Scheme 66) . Similar cyclizations of o-alkynylphenols lead to the formation of coumarins . 

His main interests include organic chemistry, heterocyclic chemistry (quinolones, dihydropyr-idines, benzimidazoles, benzotriazoles, benzoselenadiazoles, bcnzothiadiazoles, glutaric acids, enol ethers), utilization of heterocyclic compounds in the organic synthesis, and molecular spectroscopy. 

Several further species of Flindersia have been examined for alkaloids and other extractives and the chemistry of this genus has been reviewed (118). The only new alkaloid found was iflflaiamine ([a] n — 0.6° hydrate, mp 62°-63° picrate, mp 207°-209°), the sole alkaloid of the wood of Flindersia ifflaiana F. Muell. (119), which is a dihydrofuroquinoline (XX). Its structure was largely elucidated by spectroscopic measurements. Its UV- and IR-spectra showed it to be a 2-alkoxy-4-quinolone, and the NMR-spectrum showed the presence of three C-methyl groups and one A-methyl (attached to aromatic ring N), a 1,2-disubstituted benzene ring, and other evidence supporting the 2-alkoxy-4-quinolone structure. 

L. leaves, including a new quinolone alkaloid. Journal of Agricultural and Food Chemistry, 51, 890—896. 

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