Efficient Procedure for the Preparation of 2-Bromofuran and Its Application in the Synthesis of 2-Arylfurans

Raheem, Mohammed Abdul; Nagireddy, Jaipal R.; Durham, Robin; Tam, William

doi:10.1080/00397910903219534

Cited by 16 publications

(5 citation statements)

References 5 publications

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“…Briefly, this approach involves a Diels-Alder cycloaddition of furan ( 9 ) to esters of nitoacrylic acid 22 – 24 ( 12 ) and ring-opening with KHMDS as key steps. Deuteration was achieved by starting with 2-bromofuran 25 ( 10 ) and reductive dehalogenation with Zn/Cu and DCl in D 2 O. Diastereomers were separated by flash chromatography and enantiomerically pure compounds were generated by repetitive kinetic resolution with PLE (Fig. 2 and Supplemental information).…”

Section: Methodsmentioning

confidence: 99%

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Diederich

Leypold

Culka

et al. 2017

Sci Rep

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Phenazines are bacterial virulence and survival factors with important roles in infectious disease. PhzF catalyzes a key reaction in their biosynthesis by isomerizing (2 S,3 S)-2,3-dihydro-3-hydroxy anthranilate (DHHA) in two steps, a [1,5]-hydrogen shift followed by tautomerization to an aminoketone. While the [1,5]-hydrogen shift requires the conserved glutamate E45, suggesting acid/base catalysis, it also shows hallmarks of a sigmatropic rearrangement, namely the suprafacial migration of a non-acidic proton. To discriminate these mechanistic alternatives, we employed enzyme kinetic measurements and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations revealed that the activation barrier of a proton shuttle mechanism involving E45 is significantly lower than that of a sigmatropic [1,5]-hydrogen shift. QM/MM also predicted a large kinetic isotope effect, which was indeed observed with deuterated substrate. For the tautomerization, QM/MM calculations suggested involvement of E45 and an active site water molecule, explaining the observed stereochemistry. Because these findings imply that PhzF can act only on a limited substrate spectrum, we also investigated the turnover of DHHA derivatives, of which only O-methyl and O-ethyl DHHA were converted. Together, these data reveal how PhzF orchestrates a water-free with a water-dependent step. Its unique mechanism, specificity and essential role in phenazine biosynthesis may offer opportunities for inhibitor development.

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Section: Methodsmentioning

confidence: 99%

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Diederich

Leypold

Culka

et al. 2017

Sci Rep

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“…Conventionally, α‐bromination of furan rings is achieved by using bromine or N ‐bromosuccinimide as brominating agents. [ 43‐49 ] In this study, we envisaged that using LiBr/K 2 S 2 O 8 instead could be more environmentally benign and industrially accessible (Scheme 3). Methyl furan‐2‐carboxylate has been employed as the model substrate (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†

Xie

Luo

et al. 2020

Chin. J. Chem.

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Bifuranyl dicarboxylates | Homocoupling | Bromination | Green reductant Herein, we describe an environmentally benign and cost-effective protocol for the synthesis of valuable bifuranyl dicarboxylates, starting with α-bromination of readily accessible furan-2-carboxylates by LiBr and K 2 S 2 O 8. Furthermore, the bromination intermediate product 5-bromofuran-2-carboxylates were then conducted in a palladium-catalyzed reductive homocoupling reactions in the presence of alcohols to afford bifuranyl dicarboxylates. One of the final products in this protocol, *2,2'+bifuran-5,5'-dicarboxylic acid esters, are essential monomers of poly(ethylene bifuranoate), which can be served as an green and versatile alternative polymer for traditional poly(ethylene terephthalate) that is currently common in technical plastics.

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“…The yields of products 4 was calculated based on the integral ratio in the 1 HNMR spectrum. Identification of the products 4 was conducted by comparison with the 1 HNMR data reported previously (after isolation of the product by preparative TLC, see the Supporting Information): 2-(4-bromophenyl)furan( 4aa), [6a] 2-(4-fluorophenyl)furan (4ba), [30] 2-(4-chlorophenyl)furan (4ca), [6a] 2-(4-iodophenyl)furan (4da), [31] 2-(2-bromophenyl)furan (4ea), [32] 2-(4-nitrophenyl)furan (4fa), [6a] 4-(furan-2-yl)benzonitrile (4ga), [6a] 1-(4-(furan-2-yl)phenyl)ethanone (4ha), [33] 2-(4-methoxyphenyl)furan (4ia), [6a] 2-phenylfuran (4ja), [6a] 1-(5-(4-nitrophenyl)furan-2-yl)ethanone (4fc), [32] 5-(4-nitrophenyl)furan-2-carbaldehyde (4fd), [7] 4-bromo-2-(4-nitrophenyl)furan (4fe), [7] 2-(4-nitrophenyl)thiophene( 4ff), [7] 2-methyl-5-(4-nitrophenyl)thiophene (4fg), [6a] tert-butyl 2-(4-nitrophenyl)-1H-pyr-role-1-carboxylate (4fi), [7] 2,5-dimethyl-4'-nitro-1,1'-biphenyl (4fj), [35] 2,4,6-trimethyl-4'-nitro-1,1'-biphenyl (4fk), [36] 2,4,6-trimethoxy-4'nitro-1,1'-biphenyl (4fl), [37] 9-(4-nitrophenyl)anthracene (4fm), [7] 2,5-bis(4-bromophenyl)furan (5aa). [38] Characterization data for the new compounds 2-Methyl-5-(4-nitrophenyl)furan (4 fb): 1 HNMR (400 MHz, CDCl 3 ) d = 8.22 (d, J = 9.2 Hz, 2H), 7.73 (d, J = 9.2 Hz, 2H), 6.78 (d, J = 3.7 Hz, 1H), 6.16-6.14 (m, 1H), 2.41 ppm (brs, 3H); 13…”

Section: Methodsmentioning

confidence: 99%

Polyaniline‐Induced CH Arylation of Arenes with Arenediazonium Salts

Amaya

Hata

Moriuchi

2015

Chemistry A European J

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A reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg-Bachmann reaction) to give the cross-coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron-poor arenediazonium salt with an electron-rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one-electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross-coupling reaction to occur. This reaction proceeds under metal-free conditions and with no need for photonic activation.

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Efficient Procedure for the Preparation of 2-Bromofuran and Its Application in the Synthesis of 2-Arylfurans

Cited by 16 publications

References 5 publications

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†

Polyaniline‐Induced CH Arylation of Arenes with Arenediazonium Salts

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Efficient Procedure for the Preparation of 2-Bromofuran and Its Application in the Synthesis of 2-Arylfurans

Cited by 16 publications

References 5 publications

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF

Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants†

Polyaniline‐Induced CH Arylation of Arenes with Arenediazonium Salts

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Synthesis of [2,2’]Bifuranyl‐5,5’‐dicarboxylic Acid Esters via Reductive Homocoupling of 5‐Bromofuran‐2‐carboxylates Using Alcohols as Reductants^†