A short and facile synthetic route to prenylated flavones. Cyclodehydrogenation of prenylated 2′-hydroxychalcones by a hypervalent iodine reagent

́csi, Katalin Gula; Litkei, G.; Antus, S.; Gunda, T. E.

doi:10.1016/s0040-4020(98)00853-9

Cited by 17 publications

(5 citation statements)

References 20 publications

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“…Claisen-Schmidt reaction [21,30,31] Friedel-Crafts reaction [21] Heck coupling [32] Suzuki-Miyaura reaction [62] Flavonols Algar-Flynn-Oyamada reaction [21,34] Karl von Auwers reaction [60] Kostanecki methodology [29] Flavanones Intramolecular cyclisation of 2 -hydroxychalcones [36][37][38][39][40][41][42][43] Flavones Oxidative cyclisation of 2 -hydroxychalcones [44][45][46][47][48][49][50][51] Allan-Robinson reaction [21,52] Baker-Venkataraman reaction [21,54] Kostanecki reaction [55] Mentzer pyrone synthesis [57] Suzuki-Miyaura reaction [62] Isoflavones Allan-Robinson reaction [21,52] Suzuki-Miyaura reaction [62] Deoxybenzoin route [22] Reductive cleavage of isoxazoles [23] Intramolecular ketene cycloaddition followed by decarboxylation…”

Section: Chalconesmentioning

confidence: 99%

“…Regarding flavones, these compounds can be synthesised through oxidative cyclisation under several reaction conditions such as classic I2-DMSO methodology [44] or using NH4I in a solvent-free environment [45]. There has also been reported the use of phenyliodinium acetate (PIDA) [46], selenium (IV) reagents under microwave irradiation [47], indium (III) halides in a gel-silica support system [48], CuI-mediated catalysis in the ionic liquid [bmim] [NTf2] as solvent [49], diphenyl disulfide at high temperatures [50], and oxalic acid-mediated catalysis [51] to obtain flavones via chalcones. The Algar-Flynn-Oyamada methodology comprises the transformation of 2 -hydroxychalcones into flavonols (route I, Figure 3) through oxidative cyclisation mediated by hydrogen peroxide in alkaline medium [21,34,35].…”

Section: Introductionmentioning

confidence: 99%

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Stereoselective Synthesis of Flavonoids: A Brief Overview

2023

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Stereoselective synthesis has been emerging as a resourceful tool because it enables the obtaining of compounds with biological interest and high enantiomeric purity. Flavonoids are natural products with several biological activities. Owing to their biological potential and aiming to achieve enantiomerically pure forms, several methodologies of stereoselective synthesis have been implemented. Those approaches encompass stereoselective chalcone epoxidation, Sharpless asymmetric dihydroxylation, Mitsunobu reaction, and the cycloaddition of 1,4-benzoquinone. Chiral auxiliaries, organo-, organometallic, and biocatalysis, as well as the chiral pool approach were also employed with the goal of obtaining chiral bioactive flavonoids with a high enantiomeric ratio. Additionally, the employment of the Diels–Alder reaction based on the stereodivergent reaction on a racemic mixture strategy or using catalyst complexes to synthesise pure enantiomers of flavonoids was reported. Furthermore, biomimetic pathways displayed another approach as illustrated by the asymmetric coupling of 2-hydroxychalcones driven by visible light. Recently, an asymmetric transfer hydrogen-dynamic kinetic resolution was also applied to synthesise (R,R)-cis-alcohols which, in turn, would be used as building blocks for the stereoselective synthesis of flavonoids.

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Section: Chalconesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stereoselective Synthesis of Flavonoids: A Brief Overview

2023

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“…Antus et al used phenyliodine(III) diacetate to facilitate an intramolecular addition of a phenolic enone with subsequent oxidation to prepare the naturally occurring flavones kanzonol-D, kanzonol-E and yinyanghuo (Scheme 27). 33…”

Section: Scheme 26mentioning

confidence: 99%

β-Oxidation of α,β-Unsaturated Carbonyl Compounds

Sommer¹

2004

Synthesis

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The replacement of a b-hydrogen on an a,b-unsaturated carbonyl system with a non-hydrogen, non-carbon atom amounts to either a net two electron oxidation or an isohypsic substitution at the b-carbon. The resulting compounds are the functional equivalents of b-dicarbonyl derivatives. Although many methods have been developed to effect this transformation, they lack generality and the process remains an underutilized one in organic synthesis.

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“…Another method for the cyclization of o-hydroxychalcones was established by Litke et al, who used iodosobenzene diacetate (phenyliodine(III) diacetate, PIDA), a hyperva lent iodine reagent, which forms iodosylbenzene in situ [134] (Scheme 27). The same re agent was used for obtaining prenylated flavones, which are abundant in nature, from prenylated 2′-hydroxychalcones [135]. Scheme 27.…”

mentioning

confidence: 99%

Flavones and Related Compounds: Synthesis and Biological Activity

Leonte,

Ungureanu,

Zaharia

2023

Molecules

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This review focuses on the synthesis and biological activity of flavones and their related flavonoidic compounds, namely flavonols and aurones. Among the biological activities of natural and synthetic flavones and aurones, their anticancer, antioxidant, and antimicrobial properties are highlighted and detailed in this review. Starting from the structures of natural flavones acting on multiple anticancer targets (myricetin, genkwanin, and other structurally related compounds), new flavone analogs were recently designed and evaluated for their anticancer activity. The most representative compounds and their anticancer activity are summarized in this review. Natural flavones recognized for their antimicrobial properties (baicalein, luteolin, quercetol, apigenin, kaempferol, tricin) have been recently derivatized or structurally modulated by chemical synthetic methods in order to obtain new effective antimicrobial flavonoidic derivatives with improved biological properties. The most promising antimicrobial agents are systematically highlighted in this review. The most applied method for the synthesis of flavones and aurones is based on the oxidative cyclization of o-hydroxychalcones. Depending on the reaction conditions and the structure of the precursor, in some cases, several cyclization products result simultaneously: flavones, flavanones, flavonols, and aurones. Based on the literature data and the results obtained by our research group, our aim is to highlight the most promising methods for the synthesis of flavones, as well as the synthetic routes for the other structurally related cyclization products, such as hydroxyflavones and aurones, while considering that, in practice, it is difficult to predict which is the main or exclusive cyclization product of o-hydroxychalcones under certain reaction conditions.

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A short and facile synthetic route to prenylated flavones. Cyclodehydrogenation of prenylated 2′-hydroxychalcones by a hypervalent iodine reagent

Cited by 17 publications

References 20 publications

Stereoselective Synthesis of Flavonoids: A Brief Overview

Stereoselective Synthesis of Flavonoids: A Brief Overview

β-Oxidation of α,β-Unsaturated Carbonyl Compounds

Flavones and Related Compounds: Synthesis and Biological Activity

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