Synthesis and Reactivity of Electron-Deficient 3-Vinylchromones
17 Aug 2021-Vol. 05, Iss: 03, pp 255-277
TL;DR: The literature data on the methods of synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing groups at the exo-cyclic double bond are summarized and systematized for the first time in this paper.
Abstract: The literature data on the methods of synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing groups at the exo-cyclic double bond are summarized and systematized for the first time. The main methods for obtaining these compounds are Knoevenagel condensation, Wittig reaction, and palladium-catalyzed cross-couplings. The most important chemical properties are transformations under the action of mono- and dinucleophiles, ambiphilic cyclizations, and cycloaddition reactions. The cross-conjugated and polyelectrophilic dienone system in 3-vinylchromones provides their high reactivity and makes these compounds valuable building blocks for the preparation of more complex heterocyclic systems. Chemical transformations of 3-vinylchromones usually begin with an attack of the C-2 atom and are accompanied by the opening of the pyrone ring followed by recyclization, in which the carbonyl group of chromone, an exo-double bond or a substituent at it can take part. The mechanisms of the reactions are discussed, the conditions for their implementation and the yields of the resulting products are indicated. This review focuses on an analysis and generalization of the knowledge that has accumulated on the chemistry of electron-deficient 3-vinylchromones, mostly over the past 15 years.
Citations
More filters
1 citations
TL;DR: In this paper , the combination of asymmetric organocatalysis with the (pseudo)-halogen effect enables the formation of chiral norcarane scaffolds in high yields and selectivities.
1 citations
1 citations
01 Jan 2022
TL;DR: A comprehensive survey of the methodologies developed for the synthesis of 2,3-unsubstituted, 2- and 3-substitized and 2, 3-disubstitized 4 H -chromen-4-one derivatives can be found in this article .
Abstract: Chromones is a family of oxygen heterocyclic compounds whose synthetic versatility and broad spectrum of bioactive properties has been widely reported over the past decade. The increasing number of publications related to the synthesis of this heterocyclic system highlights diverse synthetic approaches, using different starting materials, with novel and efficient synthetic details, applying alternative heating conditions, that provides a huge number of polyfunctionalized 4 H -chromen-4-one derivatives. The purpose of this chapter is to present a comprehensive survey of the methodologies developed for the synthesis of 2,3-unsubstituted, 2- and 3-substituted and 2,3-disubstituted 4 H -chromen-4-ones, focusing on the literature since 2012, in nearly 450 publications.
1 citations
References
More filters
TL;DR: The main method for obtaining these compounds is the Sonogashira cross-coupling reaction of 3-halochromones with terminal acetylenes, and their most important chemical properties include the transformation into furans, reactions with dinucleophiles, ambiphilic [4+2]- and [ 4+3]-cyclizations, and also dimerization and mixed condensation of 2-methyl-3-(1-alkynyl)chromones due to the vinylogous methyl group.
Abstract: For the first time, the literature data on the methods of synthesis and reactivity of 3-(1-alkynyl)chromones are summarized and systematized. The main method for obtaining these compounds is the Sonogashira cross-coupling reaction of 3-halochromones with terminal acetylenes, and their most important chemical properties include the transformation into furans, reactions with dinucleophiles, ambiphilic [4+2]- and [4+3]-cyclizations, and also dimerization and mixed condensation of 2-methyl-3-(1-alkynyl)chromones due to the vinylogous methyl group. Except for the oxacyclization to furans, chemical transformations of 3-(1-alkynyl)chromones are accompanied by pyrone ring transformation, in which not only the carbonyl group but also the triple bond can participate. This significantly increases the synthetic value of these compounds and ensures the production of more complex heterocyclic systems based on them. The mechanisms of the reactions are discussed, the conditions for their implementation and the yields of the resulting products are indicated. The bibliography includes 80 references.
6 citations
TL;DR: In this paper, a series of 1-phenyl-3-(6-methylchromon-3-yl)-2-propen-1-one derivatives (I- XVI) of the general structural formula with substituents R- R listed in Table 1.
Abstract: There are numerous published data showing evidence of a broad spectrum of pharmacological activity inherent in 1,3-diphenylpropenone (chalcone) derivatives [1]. By substituting the residues of various heterocycles for one or both benzene nuclei in the chalcone molecule, it is possible not only to introduce an additional pharmacophore into the base structure, but to modify more significantly (as compared to simple functionalization of the benzene nucleus) the character of electron density distribution on the propenone fragment. In our opinion, selection of the chromon-3yl residue can simultaneously increase the antiallergic activity and decrease the toxicity of chalcone derivatives [2 – 4]. In accordance with this prognosis, we have synthesized a series of 1-phenyl-3-(6-methylchromon-3-yl)-2-propen-1-one derivatives (I – XVI) of the general structural formula With substituents R – R listed in Table 1.
6 citations
TL;DR: Predictive study for the biological activities using PASS (prediction of activity spectra for biologically active substances) online software showed optimistic activities for oxocinols 3a–e in the treatment of cancer, influenza A and microbial infections.
Abstract: A new promising protocol has been developed for the synthesis of scarce oxocine derivatives 3a–e and 6 through addition of amine-based nucleophiles such as hydroxylamine hydrochloride, primary amine and hydrazide to chromonylidene benzothiazol-2-ylacetonitrile 2 in refluxing dioxane under metal free reaction conditions in moderate to good yields. Other nitrogen nucleophiles such as piperidine, hydrazine and thiosemicarbazide failed to afford the corresponding oxocinols, and instead pyridine derivatives 7, 8 and 10 were obtained exclusively. Predictive study for the biological activities using PASS (prediction of activity spectra for biologically active substances) online software showed optimistic activities for oxocinols 3a–e in the treatment of cancer, influenza A and microbial infections. Additionally, DFT studies of oxocine derivatives 3a–e and 6 indicated the presence of required thermodynamics parameters for the application in dye-sensitized solar cells (DSSCs).
6 citations
TL;DR: It is shown that the tuning of the selectivity toward the kinetic product could be achieved by key structural modifications of the different reaction partners involved in the domino process.
Abstract: Two successive original routes leading to two novel families of polyheterocycles starting from the versatile chromone-based Michael acceptors platform are reported herein. The major aspect of this work is the selective access to these frameworks by changing the course of the domino process involved in their formation. First, enaminochromanones were selectively accessed under uncommon kinetic control. In this study, we showed that the tuning of the selectivity toward the kinetic product could be achieved by key structural modifications of the different reaction partners involved in the domino process. Once selectivity was efficiently controlled, enaminochromanones were ultimately transformed into a more complex family of polyheterocycles containing the pyrrolo-oxazinone framework. Here, the modulation of the domino sequence toward these particularly scarce structures was enabled by a pivotal switch in reactivity induced by aryl-λ3-iodanes.
5 citations
TL;DR: Condensates 4−6 undergo reductive dimerization with Sm in THF containing aqueous NH4Cl to produce 7−9, whereas with Zn under similar reaction condition 3−5 produce 10−12.
5 citations