Novel access to 2-substituted quinolin-4-ones by nickel boride-mediated reductive ring transformation of 5-(2-nitrophenyl)isoxazoles

Lohrer, Bernhard; Bracher, Franz

doi:10.1016/j.tetlet.2019.151327

Cited by 4 publications

(4 citation statements)

References 42 publications

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“…Overall, the described synthetic approach ( Scheme 1 and Scheme 2 ) allowed us to prepare in an operationally simple manner 2-alkyl-4-quinolones 8a – d , all of which are known from the literature [ 25 , 36 , 61 , 67 – 68 ] and two of them are natural products of microbial origin ( 8c [ 69 ] and 8d [ 70 ]). More importantly, the utility of the approach was demonstrated with the synthesis of the novel 2-alkyl-4-quinolone-3-carboxamides 5a – i and some of their N -hydroxy derivatives 4a – e .…”

Section: Resultsmentioning

confidence: 99%

“…This, along with the importance of the C-3 substitution in analogues of microbial behavioral modulators [ 54 , 56 ], prompted us to investigate a new synthetic approach that could provide a straightforward access to both 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides. Our approach falls within the broader methodological group of reductive cyclizations of o -nitrobenzoyl ketones [ 57 – 58 ], enamines [ 59 – 60 ], or isoxazoles [ 61 ]. The scope of these reductive cyclizations is limited by the availability of the necessary intermediates and has remained largely underexplored, especially with regard to 4-quinolones with long-chain substituents at the C-2 position.…”

Section: Introductionmentioning

confidence: 99%

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Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

Mollova-Sapundzhieva,

Angelov,

Georgiev

et al. 2023

Beilstein J. Org. Chem.

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β-Keto amides were used as convenient precursors to both 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides. The utility of this approach is demonstrated with the synthesis of fourteen novel and four known quinolone derivatives, including natural products of microbial origin such as HHQ and its C5-congener. Two compounds with high activity against S. aureus have been identified among the newly obtained quinolones, with MICs ≤ 3.12 and ≤ 6.25 µg/mL, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

Mollova-Sapundzhieva,

Angelov,

Georgiev

et al. 2023

Beilstein J. Org. Chem.

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“…The reaction showed a broad substrate scope and a variety of substituted isoxazoles reacted smoothly under the optimized reaction conditions to yield the desired 2-substituted-4-quinolones in good yields (62-79 %). [42] Gore et al, unfolded a highly efficient, environmentally benign approach for the synthesis of 2,3 disubstituted-4quinolone (9) by reacting various substituted 3-(2-halophenyl)-3-oxopropanes with different aldehydes in the presence of aq. NH 3 as a nitrogen source and water as an eco-friendly reaction medium.…”

Section: Metal Assisted Synthesis Of 4-quinolonesmentioning

confidence: 99%

Recent Developments in the Synthetic Strategies of 4‐Quinolones and Its Derivatives

2020

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The ubiquitous presence of 4-quinolones and its derivatives in a wide range of natural as well as synthetic drug molecules made them molecule of utmost importance for organic and medicinal chemists. Their wide array of biological activities such as antimicrobial, anticancer, anti-HIV, genitourinary infection, antifilarial, etc., has augmented their appeal both for synthetic and medicinal chemistry campaigns. Moreover, they are valuable intermediates for the synthesis of various fused heterocyclic compounds of synthetic and medicinal importance. Considering their array of synthetic and biological importance, new strategies for the synthesis of 4-quinolones and their derivatives have been designed and successfully demonstrated by researchers around the globe. The present review covers recent advances in the synthetic chemistry of 4quinolones since 2015 along with an insight into their mechanistic studies. We hope that the review article will serve as a valuable tool for the scientific community engaged in the synthesis and utilization of 4-quinolones and their derivatives.

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“…C NMR (DMSO-d 6 , 100 MHz): 177.0, 148.9, 140.5, 133.3, 131.9, 129.5, 124.9, 124.7, 124.0, 123.4, 118.7, 107.5 ppm. 2-(4-Carbomethoxyphenyl)quinolin-4(1H)-one (2j)[74]. Pink solid (116 mg, 83% yield) 1.…”

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confidence: 99%

Effective Synthesis of 4-Quinolones by Reductive Cyclization of 2′-Nitrochalcones Using Formic Acid as a CO Surrogate

Ferretti,

Fouad,

Abbo

et al. 2023

Molecules

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4-Quinolones are the structural elements of many pharmaceutically active compounds. Although several approaches are known for their synthesis, the introduction of an aryl ring in position 2 is problematic with most of them. The reductive cyclization of o-nitrochalcones by pressurized CO, catalyzed by ruthenium or palladium complexes, has been previously reported to be a viable synthetic strategy for this aim, but the need for pressurized CO lines and autoclaves has prevented its widespread use. In this paper, we describe the use of the formic acid/acetic anhydride mixture as a CO surrogate, which allows us to perform the reaction in a cheap and commercially available thick-walled glass tube without adding any gaseous reagent. The obtained yields are often high and compare favorably with those previously reported by the use of pressurized CO. The procedure was applied to a three-step synthesis from commercially available and cheap reagents of the alkaloid Graveoline.

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Novel access to 2-substituted quinolin-4-ones by nickel boride-mediated reductive ring transformation of 5-(2-nitrophenyl)isoxazoles

Cited by 4 publications

References 42 publications

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

Recent Developments in the Synthetic Strategies of 4‐Quinolones and Its Derivatives

Effective Synthesis of 4-Quinolones by Reductive Cyclization of 2′-Nitrochalcones Using Formic Acid as a CO Surrogate

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