Synthesis, absolute configuration and intermediates of 9-fluoro-6,7-dihydro-5-methyl-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acid (flumequine)

Bálint, József; Egri, Gabriella; Fogassy, Elemér; Böcskei, Zsolt; Simon, Kálmán; Gajáry, Antal; Friesz, A.

doi:10.1016/s0957-4166(99)00071-3

Cited by 56 publications

(44 citation statements)

References 3 publications

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“…gave 20b in 78% yield and7 9:21 er within 24 h. Better results were obtained for 2-fluoro-2-methylquinoline( 19c), which afforded 20c in 93% yield and 90:10 er within 10 h. Notably, 20c is ak ey intermediate in the synthesis of antibacterial agent (S)-flumequine. [21] Theh igher enantioselectivity observed for 19c seems to imply that enhancede lectrophilicityo fi miniums pecies 6 (Scheme 1) may be important in differentiating enantiomers during the finalh ydride addition. This observation,i nt urn, mayp rovide additional cursorys upport for an outer-spherer eactionm echanism (vide supra).…”

Section: Resultsmentioning

confidence: 99%

Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N‐Ferrocenyl NHC‐Iridium Complex

John¹,

Wilson‐Konderka²,

Metallinos³

2015

Adv Synth Catal

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Annulated planar chiral N-ferrocenylimidazolones,o btainedb ya cid-mediated cyclization of diphenylmethanol derivatives,m ay be reduced with diisobutylaluminium hydide (DIBAL-H) to afford as eries of surprisingly stable and isolable hemiaminal ether aminals. Tw oo ft hese derivatives can be oxidized with triphenylcarbenium tetrafluoroborate to imidazolinium salt precursors of N-heterocyclic carbenes (NHCs). Deprotonation of these salts in the presenceo f( cyclooctadiene)iridium chloride dimer {[Ir(COD)Cl] 2 }p rovides chiral coordination complexes bearing N-ferrocenyl NHCsw ith unique rigid tetracyclic frameworks.C ationic analogues of these complexes catalyze the asymmetric hydrogenation of 2-substituted quinolines under very mild conditions( 1mol% complex, 1mol% PPh 3 ,1 -5 atm H 2 , toluene,2 5 8 8 C) in appreciable enantioselectivity (up to 90:10 er). Thes ensitivityo ft he hydrogenation process to changes in the phosphineadditive suggests that an outer-sphere reactionm echanism may be involved, as proposed for ar elated achiral NHC-Ir complexr eported by Crabtree and co-workers.

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Section: Resultsmentioning

confidence: 99%

Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N‐Ferrocenyl NHC‐Iridium Complex

John¹,

Wilson‐Konderka²,

Metallinos³

2015

Adv Synth Catal

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“…They possess high reactivity, wide diversity of chemical properties, and a large area of practical application [1]. 1,2,3,4-Tetrahydroquinoline system underlies many bioactive natural substances [2][3][4][5][6][7][8] and potential drugs [9][10][11]. The development of medicinal chemistry is an important initiator of the progress in new methods of synthesis of tetrahydroquinoline derivatives, in particular, of monoand polyhalo derivatives.…”

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confidence: 99%

“…At the bromination of 2-phenyl-1,2,3,4-tetrahydroquinoline 4 with bromine in chloroform at the temperature of -20 о С and with N-bromosuccinimide at stirring for 3 h at room temperature in solvents mixture (chloroform-tetrachloromethane) along with the bromination the oxidation of the heterocyclic ring of DOI: 10 The structure of 3,6,8-tribromo-2-phenylquinoline 5 is established by the X-ray diffraction (XRD) method. Crystals for XRD experiment were obtained by slow evaporation of the benzene solution.…”

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Bromination of 2-phenyl-1,2,3,4-tetrahydroquinolines

et al. 2015

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Bromination of 2-phenyltetrahydroquinolines derivatives was investigated. During the bromination of 2-phenyl-1,2,3,4-tetrahydroquinoline with bromine in chloroform or bromosuccinimide along with the formation of di-and tribrom derivatives the oxidation reaction occurs with the generation of quinoline structure. The interaction of 2-phenyl-1,2,3,4-tetrahydroquinoline with bromine in acetic acid leads to the formation of 6,8-dibromoderivative preserving the 1,2,3,4-tetrahydroquinoline ring. At the same time Nsubstituted 2-phenyl-1,2,3,4-tetrahydroquinoline is selectively brominated in various conditions with the formation of 6-monobromoderivative. By the method of X-ray diffraction analysis the molecular structure of 3,6,8-tribromo-2-phenylquinoline single crystals was determined.

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“…It was shown that the optical isomers of Flumequine have markedly different antibacterial potency. 1 FTHQ has so far been resolved by two methods: Rohlfing et al 1 separated the enantiomers via covalently bonded diastereoisomeric amides of N-tosyl-(S)-proline, while recently we reported on the optical resolution by diastereoisomeric salt formation with 3-bromocamphor-8-sulfonic acid 2 and the Nphtaloyl derivative of the (R)-FTHQ. 3 In the present study we describe the optical resolution by a commercially available resolving agent (DPTTA) by a nonconventional method.…”

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confidence: 99%

“…RESULTS AND DISCUSSION Chiral Recognition in Supercritical CO 2 A series of SFE experiments was carried out with different resolving agents at a molar ration of 0.5 to select the most effective ones. The extraction pressure was 160 bar and the temperature 39°C at each run.…”

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Optical resolution of 6‐fluoro‐2‐methyl‐1,2,3,4‐tetrahydroquinoline by supercritical fluid extraction

et al. 2001

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6-Fluoro-2-methyl-1,2,3,4-tetrahydroquinoline (FTHQ) enantiomers were separated by supercritical fluid extraction using carbon dioxide. Diastereoisomeric salts were formed from the racemic base with less than one equivalent of O,O'-di-(4-toluoyl)-(2R,3R)-tartaric acid (DPTTA). Further purification was achieved by partial salt formation of the enantiomeric mixture with an achiral acid (HCl) followed by the supercritical fluid extraction of the free enantiomers.

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Synthesis, absolute configuration and intermediates of 9-fluoro-6,7-dihydro-5-methyl-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acid (flumequine)

Cited by 56 publications

References 3 publications

Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N‐Ferrocenyl NHC‐Iridium Complex

Low Pressure Asymmetric Hydrogenation of Quinolines using an Annulated Planar Chiral N‐Ferrocenyl NHC‐Iridium Complex

Bromination of 2-phenyl-1,2,3,4-tetrahydroquinolines

Optical resolution of 6‐fluoro‐2‐methyl‐1,2,3,4‐tetrahydroquinoline by supercritical fluid extraction

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