Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Metal- and Solvent-Free Approach to Access 3-Se/S-Chromones from the Cyclization of Enaminones in the Presence of Dichalcogenides Catalyzed by KIO₃.

ABSTRACT: Herein, we describe a greener protocol for the one-pot synthesis of 3-Se/S-4H-chromen-4-ones. The desired products were obtained in good to excellent yields using 2-hydroxyphenyl enaminones and half equivalents of various odorless diorganyl dichalcogenides (S/Se) in the presence of glycerol (5 molar equiv) and KIO₃ (15 mol %) as the catalyst under solvent-free conditions.

SUBMITTER: Rafique J

PROVIDER: S-EPMC6641037 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Metal- and Solvent-Free Approach to Access 3-Se/S-Chromones from the Cyclization of Enaminones in the Presence of Dichalcogenides Catalyzed by KIO3.

Rafique Jamal J Saba Sumbal S Schneider Alex R AR Franco Marcelo S MS Silva Symara M SM Braga Antonio L AL

ACS omega 20170524 5

Herein, we describe a greener protocol for the one-pot synthesis of 3-Se/S-4H-chromen-4-ones. The desired products were obtained in good to excellent yields using 2-hydroxyphenyl enaminones and half equivalents of various odorless diorganyl dichalcogenides (S/Se) in the presence of glycerol (5 molar equiv) and KIO3 (15 mol %) as the catalyst under solvent-free conditions. ...[more]

PMID: 31457578

Similar Datasets

Selectfluor-mediated tandem cyclization of enaminones with diselenides toward the synthesis of 3-selenylated chromones.

Project description:A practical and metal-free approach for the regioselective selenation of chromones employing Selectfluor reagent under mild conditions is described. The developed method is suitable for a wide substrate scope and affords 3-selenylated chromones in good to excellent yield with high selectivity. An ionic mechanism is proposed for this transformation. Furthermore, the application of potassium thiocyanate with enaminones for the synthesis of thiocyano chromones in this transformation is also successful.

| S-EPMC10486202 | biostudies-literature

One-Pot Regio- and Diastereoselective Gold-Catalyzed Propargylation of in Situ Activated Chromones and Consecutive Cyclization.

Project description:Herein, we report a gold-catalyzed propargylation of chromone derivatives by propargylsilanes. Chromones are synergistically activated by the silylium cation resulting from the gold activation of the propargylsilane. The reaction exclusively occurs at the C2-position of the chromone, and a single diastereoisomer is formed. Computational studies performed on the reaction mechanism rationalize the formation of the preferred diastereoisomer. Finally, a dual consecutive cascade reaction based on different gold catalysts enables the formation of complex tricyclic compounds.

| S-EPMC11650761 | biostudies-literature

Rhodaelectro-catalyzed access to chromones via formyl C-H activation towards peptide electro-labeling.

Project description:Chromones represent a privileged scaffold in medicinal chemistry and are an omnipresent structural motif in natural products. Chemically encoded non-natural peptidomimetics feature improved stability towards enzymatic degradation, cell permeability and binding affinity, translating into a considerable impact on pharmaceutical industry. Herein, a strategy for the sustainable assembly of chromones via electro-formyl C-H activation is presented. The rational design of the rhodaelectro-catalysis is guided by detailed mechanistic insights and provides versatile access to tyrosine-based fluorogenic peptidomimetics.

| S-EPMC8342597 | biostudies-literature

Synthesis of 3-CF2-Containing Chromones via a Visible-Light-Induced Radical Cascade Reaction of o-Hydroxyaryl Enaminones.

Project description:A general and efficient visible-light-induced CF2 radical-based cascade reaction of o-hydroxyaryl enaminones has been described. This protocol afforded the corresponding functionalized 3-CF2-containing chromones in generally good yields under mild reaction conditions. The use of NaHSO3, which has both basicity and reducibility, efficiently suppressed the formation of two byproducts, 4H-chromen-4-one and 3-bromo-4H-chromen-4-one.

| S-EPMC6641644 | biostudies-literature

Bronsted acid mediated cyclization of enaminones. Rapid and efficient access to the tetracyclic framework of the Strychnos alkaloids.

Project description:The development of an efficient diastereoselective method that permits rapid construction of the tetracyclic core 17 of the Strychnos-Aspidosperma alkaloids is described. Enaminone 16, synthesized in high yield, has been cyclized under the influence of a Brønsted acid to provide the core tetracyclic framework 17 of the Strychnos alkaloids in optically active form or alternatively to the β-ketoester tetrahydro-β-carboline (THBC) unit 18, by varying the equivalents of acid and the molar concentration. Attempts to utilize 18 to form the C₇-C₁₆ bond of the akuammiline related alkaloids represented by strictamine (22), using metal-carbenoid chemistry, are also described.

| S-EPMC3288251 | biostudies-literature

Three-component synthesis of cyclic enaminones via ketene cyclization.

Project description:Cyclic six-membered enaminones were synthesized from three components (bromodiazoacetone, primary amine, and alkyne) in high yields via aza-Michael addition, Wolff rearrangement, and nucleophilic ketene cyclization.

| S-EPMC3099226 | biostudies-literature

Solvent-controlled photocatalytic divergent cyclization of alkynyl aldehydes: access to cyclopentenones and dihydropyranols.

Project description:Divergent synthesis is a powerful strategy for the fast assembly of different molecular scaffolds from identical starting materials. We describe here a solvent-controlled photocatalytic divergent cyclization of alkynyl aldehydes with sulfonyl chlorides for the direct construction of highly functionalized cyclopentenones and dihydropyranols that widely exist in bioactive molecules and natural products. Density functional theory calculations suggest that a unique N,N-dimethylacetamide-assisted 1,2-hydrogen transfer of alkoxy radicals is responsible for the cyclopentenone formation, whereas a C-C cleavage accounts for the selective production of dihydropyranols in acetonitrile and water at 50 °C. Given the simple and mild reaction conditions, excellent functional group compatibility, forming up to four chemical bonds, and tunable selectivity, it may find wide applications in synthetic chemistry.

| S-EPMC8409468 | biostudies-literature

Palladium-catalyzed intramolecular carbopalladation/cyclization cascade: access to polycyclic N-fused heterocycles.

Project description:An efficient palladium-catalyzed intramolecular carbopalladation/cyclization cascade toward tetra- and pentacyclic N-fused heterocycles has been developed. This transformation proceeds via the palladium-catalyzed coupling of aryl halides with internal propargylic esters or ethers followed by the 5-endo-dig cyclization leading to polycyclic pyrroloheterocycles in moderate to excellent yields.

| S-EPMC3131228 | biostudies-literature

Asymmetric Gold(I)-Catalyzed Tandem Hydroarylation-Nazarov Cyclization: Enantioselective Access to Cyclopentenones.

Project description:The asymmetric synthesis of cyclopentachromenones from gold-catalyzed reaction of readily available skipped alkenynones is described. This cascade reaction involves an initial anti-Michael hydroarylation of the ynone moiety to form a gold-functionalized dialkenylketone intermediate, followed by a Nazarov cyclization that proceeds in an unprecedented enantioselective manner. Excellent enantiomeric ratios and chemical yields are obtained under mild reaction conditions.

| S-EPMC9544548 | biostudies-literature

Intrinsic Thermal conductivities of monolayer transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te).

Project description:The successful synthesis of the single to few layer transition metal dichalcogenides has opened a new era in the nanoelectronics. For their efficient implementations in the electronic devices while taking care of their overheating issues, the characterization of their thermal transport properties is extremely vital. So, we have systematically investigated the thermal transport properties of monolayer transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te) by combining the first-principles calculations with Boltzmann transport equation. We find that monolayer WTe2 possesses the lowest lattice thermal conductivity κL (33:66 Wm-1K-1 at 300 K) among these six semiconducting materials, in contrast to the highest κL (113:97 Wm-1K-1 at 300 K) of WS2 among them. Further analyses reveal that the higher (lower) anharmonic and isotopic scatterings together with the lower (higher) phonon group velocities lead to the lowest (highest) value of κL in WTe2 (WS2) monolayer. In addition, we have also calculated the cumulative thermal conductivity κC as a function of mean free path, which indicates that the nanostructures with the length of about 400 nm would reduce κL drastically. These results offer important understanding from thermal conductivity point of view to design the 2D transition metal dichalcogenides MX2 (M = Mo, W; X = S, Se, Te) electronics.

| S-EPMC6418116 | biostudies-literature