Efficient visible light mediated synthesis of quinolin-2(1<i>H</i>)-ones from quinoline<i>N</i>-oxides

Mandal, Swarup; Bhuyan, Samuzal; Jana, Saibal; Hossain, Jagir; Chhetri, Karan; Roy, Biswajit

doi:10.1039/d1gc01460a

Cited by 17 publications

(10 citation statements)

References 51 publications

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“…Many convenient approaches are available to synthesize acridinium salts that can serve as potential visible-light photocatalysts . Mes-Acr-Me + is a powerful oxidant that activates many chemical systems in the presence of visible light. ,− We have also shown earlier that the N–Cl bond of N -chlorosuccinimide could be activated by the use of the Mes-Acr-MeClO 4 photocatalyst (Figure b) …”

Section: Introductionmentioning

confidence: 99%

Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Dinda

Mal

2022

J. Org. Chem.

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Herein, we report the activation of the C−Br bond of CBrX 3 (X = Cl, Br) using 9-mesityl-10-methylacridinium perchlorate as a visiblelight (12W blue LED, 450−455 nm) photocatalyst for the synthesis of gemdihaloenones from terminal alkynes. An electron transfer from CBrX 3 to Mes-Acr-MeClO 4 led to the formation of •+ CBrX 3 which subsequently resulted in the intermediate + CX 3 . Next, C−C cross-coupling of + CX 3 with terminal alkynes was the key path to obtain the gem-dihaloenones. Radical trapping experiments with TEMPO, BHT, and Stern−Volmer quenching studies helped to understand that the reaction proceeded via the SET mechanism.

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Section: Introductionmentioning

confidence: 99%

Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Dinda

Mal

2022

J. Org. Chem.

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“…In order to do that we preferred to explore the possibility of using the visible light photocatalytic method by choosing easily synthesizable benzyl ether of high boiling heptanol, 2 , as our model compound so that the isolated yield of deprotected alcohol could be measured without worrying about evaporative weight loss during workup. To start with we irradiated methanolic solution of 2 with blue LED light in presence of 1 mol% of a recently developed photo‐catalyst A, [21,22a,b] and 0.5 equiv. of DDQ in ambient condition and open air.…”

Section: Resultsmentioning

confidence: 99%

Efficient Greener Visible‐Light‐Catalyzed Debenzylation of Benzyl Ethers and Esters: A Gateway to Wider Exploitation of Stable Benzyl Protecting Groups

et al. 2022

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A non-hydrogenolytic mild deprotection strategy for stable benzyl protection of hydroxyl group is one of the long-cherished goals in multistep synthesis involving carbohydrates or compounds with multiple hydroxyl groups. A greener organo-photocatalytic method has been developed for mild and efficient visible light catalytic deprotection of benzyl group from benzyl ether and benzyl ester. The newly developed method in ambient condition with only 1 mol% of catalyst loading can efficiently remove highly stable benzyl protection from ethers and esters of wide substrate scope with excellent functional group tolerance, thus proved to be suitable for final stage deprotection. Employment of molecular oxygen as terminal oxidant and excellent yield in the multigram scale reaction signifies the eco-friendliness, robustness and industrial applicability of the method.

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“…[42] Very recently, Roy and co-workers reported a visible light triggered synthesis of quinolin-2(1H)-ones 44 from quinolin N-oxides 16 under visible light illumination (Scheme 18). [11] The reaction demonstrated a good functional group compatibility with high reaction efficiency. Interestingly, C-8 substituted quinoline N-oxides gave higher yields in comparison to quinoline N-oxides having substituents at other positions.…”

Section: Alkylation and Acylationmentioning

confidence: 95%

Visible‐Light‐Mediated C‐2 Functionalization and Deoxygenative Strategies in Heterocyclic N‐Oxides

2022

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Heterocyclic N-oxides are prevalent in numerous natural products with broad applications in pharmaceuticals, agrochemicals, material sciences, and asymmetric synthesis. Owing to their profound biological and physiological activity and unique chemical reactivity, the importance of these compounds has stimulated substantial interest among organic synthetic chemists. More importantly, C-2 functionalization of heterocyclic N-oxides, including pyridine-, isoquinoline-, pyrazine-, quinoxaline-, and quinoline N-oxides, is among the most important strategies for heterocyclic functionalization. Besides, deoxygenation of heterocyclic N-oxides has also emerged as a reaction of significance in organic chemistry. In the past decade, visible light photoredox catalyzed C-2 functionalization and deoxygenation of these heterocyclic N-oxides have drawn substantial attention owing to their mild reaction conditions. This review has been categorized based on visiblelight-mediated nondeoxygenative C-2 functionalization (alkylation, fluoroalkylation, arylation, acylation, and amination), deoxygenative C-2 functionalization (sulfonylation, alkynylation, alkylation, and acylation), and deoxygenation (without CÀ H functionaliza-tion) of heterocyclic N-oxides. For most part of the work, the substrate scope, limitation, and mechanism of the reactions have been discussed.

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Efficient visible light mediated synthesis of quinolin-2(1H)-ones from quinolineN-oxides

Abstract: Quinolin-2(1H)-ones are prevalent in natural products and pharmacologically useful compounds. Here we present an unconventional and hitherto unknown photocatalytic approach to their synthesis from easily available quinoline-N-oxides.

Cited by 17 publications

References 51 publications

Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Efficient Greener Visible‐Light‐Catalyzed Debenzylation of Benzyl Ethers and Esters: A Gateway to Wider Exploitation of Stable Benzyl Protecting Groups

Visible‐Light‐Mediated C‐2 Functionalization and Deoxygenative Strategies in Heterocyclic N‐Oxides

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Efficient visible light mediated synthesis of quinolin-2(1H)-ones from quinolineN-oxides

Abstract: Quinolin-2(1H)-ones are prevalent in natural products and pharmacologically useful compounds. Here we present an unconventional and hitherto unknown photocatalytic approach to their synthesis from easily available quinoline-N-oxides.

Cited by 17 publications

References 51 publications

Activation of C–Br Bond of CBr4 and CBrCl3 Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Activation of C–Br Bond of CBr4 and CBrCl3 Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Efficient Greener Visible‐Light‐Catalyzed Debenzylation of Benzyl Ethers and Esters: A Gateway to Wider Exploitation of Stable Benzyl Protecting Groups

Visible‐Light‐Mediated C‐2 Functionalization and Deoxygenative Strategies in Heterocyclic N‐Oxides

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Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst

Activation of C–Br Bond of CBr₄ and CBrCl₃ Using 9-Mesityl-10-methylacridinium Perchlorate Photocatalyst