Solvent‐Switchable Regioselective Synthesis of Aurones and Flavones Using Palladium‐Supported Amine‐Functionalized Montmorillonite as a Heterogeneous Catalyst

Chavan, Sujit P.; Varadwaj, G. Bishwa Bidita; Parida, Kulamani; Bhanage, Bhalchandra M.

doi:10.1002/cctc.201600549

Cited by 26 publications

(14 citation statements)

References 53 publications

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“…A similar reaction was described by Chavan and co-workers, who used Pd 0 complexed with 3-aminopropyl-triethoxysilane (APTES@K10) as the catalyst [ 64 ]. Additionally, in this case, the reaction of ortho -iodo-phenols 57 with terminal alkynes 54 resulted in the target 6:5 aurones 55 , which were eventually isolated with the upper 6:6 counterpart flavones 56 .…”

Section: Synthetic Strategies To Obtain Auronesmentioning

confidence: 99%

Aurones: A Golden Resource for Active Compounds

2021

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Deemed as poorly represented in nature, aurones have been often overlooked by researchers compared to other members of the flavonoid superfamily. However, over the past two decades, they have been reassessed by the scientific community, who are increasingly appreciating their ability to modulate several biological pathways. This review summarizes the recent literature on this class of compounds, which has been analyzed from both a chemical and a functional point of view. Original articles, reviews and editorials featured in Pubmed and Scifinder over the last twenty years have been taken into account to provide the readers with a view of the chemical strategies to obtain them, their functional properties, and their potential of technological use. The resulting comprehensive picture aims at raising the awareness of these natural derivatives as effective drug candidates, fostering the development of novel synthetic analogues.

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Section: Synthetic Strategies To Obtain Auronesmentioning

confidence: 99%

Aurones: A Golden Resource for Active Compounds

2021

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“…Bhanange et al developed a well characterized heterogeneous catalyst named as Pd(0)APTES@K10 (APTES = (3-aminopropyl)-triethoxysilane) for the regio-selective synthesis of aurons and flavones via carbonylative cyclization of 2-amino-phenol and alkynes (Scheme 62). [85] They have demonstrated the regioselective synthesis of 5-exo (aurones) and 6-endo (flavones) products under different solvent conditions. Mild reaction conditions, recyclable catalyst (4 cycles) and greater selectivity of the products were the advantages of the process.…”

Section: Synthesis Of Aurones and Flavonesmentioning

confidence: 99%

Supported Palladium Catalyzed Carbonylative Coupling Reactions using Carbon Monoxide as C1 Source

Shaifali

Sheetal

Das

2021

The Chemical Record

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The carbonylative reactions of aryl halides, boronic acids, amines, activated alkene and alkynes under CO and supported palladium catalyzed conditions are very popular reactions for the synthesis of bioactive molecules, pharmaceuticals, polymers, peptides, intermediates and fine chemicals synthesis. Due to cost effectiveness and easy handling of recyclable supported palladium catalyst, it became more popular among researchers either working in academic institute or industry. In recent years, irrespective of poisoning effect of CO with palladium as major limitation, several advancements have been done through surface selection, designing and condition improvement to achieve high yield in the area of carbonylative coupling reactions. We hope this review will be helpful as a ready reference of last 20 years in the field of CO insertion reactions using diverse range of supported palladium catalysts under carbon monoxide or its sources as C1 source.

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“…However, aurones (2-benzylidene-coumaran-3-one and its derivatives), a class of minor flavonoids that naturally occur in limited plants such as Antirrhinum majus and Cosmos , possess an unusual 5-membered C-ring because of an exceptional mechanism (Figure I). , Aurones are biosynthesized directly from chalcones via the oxidation of B-rings mainly by polyphenol oxidases (PPO), such as aureusidin synthase (AmAS1) , and aurone synthase (AUS1), or by peroxidases (PRX), such as MtPRXs. , Therefore, the chemical catalytic transformation from simple chalcones into aurones that do not occur naturally is attractive, which overcomes the drawback of known limited enzyme catalysis. Further, the above-mentioned transformation is one of the most useful synthetic methods to produce aurones as compared with that of the other synthetic methods − because chalcones are easily available through synthesis from simple aldehydes and ketones via the Claisen–Schmidt condensation or by extracting from the plants. Recently, various biological activities of aurones have also been revealed along with those of other flavonoids, − which have elevated the importance of the transformation into novel aurones in terms of their pharmaceutical application.…”

Section: Introductionmentioning

confidence: 99%

Unusual Olefinic C–H Functionalization of Simple Chalcones toward Aurones Enabled by the Rational Design of a Function-Integrated Heterogeneous Catalyst

et al. 2018

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Flavonoids, which are ubiquitous plant secondary metabolites obtained from chalcones, mostly possess 6membered C-rings derived from 6-endo-trig cyclization of chalcones. However, aurones, which are a class of flavonoids that rarely occur naturally, possess unusual 5-membered Crings biosynthesized from chalcones by mainly performing Bring oxidation. Therefore, the chemical catalytic transformation from simple chalcones into aurones is attractive, because it overcomes the drawback of known limited enzyme catalysis. The catalytic transformation, however, has not yet been reported because of the preferential 6-membered ring formation as with the biosynthesis and the need for rare intramolecular olefinic C−H functionalization. Here, we developed the catalytic olefinic C−H functionalization of simple chalcones toward various aurones enabled by the rational design of a function-integrated heterogeneous catalysta Pd-on-Au bimetallic nanoparticle catalyst supported on CeO 2 using O 2 in air as the sole oxidant without any additives. In this system, the four conditions that were required for the challenging transformation toward aurones were achieved by the respective components of the catalyst: (a) a supported Pd catalyst: a catalyst for the olefinic C−H functionalization of chalcones toward aurones, (b) an Au promoter: an improvement in the catalytic activity by stabilizing Pd(0), (c) a CeO 2 support: the inhibition of the 6-endo-trig cyclization utilizing the adsorption of chalcones, and (d) a Pd-on-Au structure: the inhibition of Au-catalyzed flavone synthesis. This catalytic transformation will promote not only the pharmaceutical study of aurones but also the rational design of a heterogeneous catalyst for the development of organic reactions that are not yet realized by homogeneous catalysts or biocatalyst.

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Solvent‐Switchable Regioselective Synthesis of Aurones and Flavones Using Palladium‐Supported Amine‐Functionalized Montmorillonite as a Heterogeneous Catalyst

Cited by 26 publications

References 53 publications

Aurones: A Golden Resource for Active Compounds

Aurones: A Golden Resource for Active Compounds

Supported Palladium Catalyzed Carbonylative Coupling Reactions using Carbon Monoxide as C1 Source

Unusual Olefinic C–H Functionalization of Simple Chalcones toward Aurones Enabled by the Rational Design of a Function-Integrated Heterogeneous Catalyst

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