Synthesis of new thioxanthenes by organocatalytic intramolecular Friedel–Crafts reaction

Yıldız, Tülay

doi:10.1080/00397911.2018.1482351

Cited by 11 publications

(8 citation statements)

References 31 publications

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“…Initially, using a metal-free nucleophilic aromatic substitution (S N Ar) reaction ,,− and a Grignard reaction, we synthesized starting chemicals in two steps (Scheme ). Then, with good yields (95–100%), we produced the required diaryl secondary alcohols with a thioether group as reagents ( 1a – 1t ).…”

Section: Resultsmentioning

confidence: 99%

“…As a result, 19 thioxanthene derivatives ( 2a – 2t ) were synthesized by the intramolecular FCA method using TFA as a catalyst in this study. Four of these compounds ( 2b , 2c , 2d , and 2e ) were synthesized in our previous study; their yields were further increased in this work. The other 15 compounds were synthesized for the first time, and their structures were elucidated by spectroscopic methods.…”

Section: Introductionmentioning

confidence: 99%

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Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Deniz,

Yıldız,

Başpınar Küçük

2024

ACS Omega

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In this study, a series of halogen-substituted thioxanthenes were synthesized because the most important and biologically active derivatives of xanthenes are thioxanthenes. In order to obtain new thioxanthene derivatives, first, the starting molecules were synthesized by the appropriate reaction methods in two steps. The intramolecular Friedel−Crafts alkylation (FCA) method was used to convert the prepared three aromatic substituted starting alcohol compounds to their corresponding thioxanthenes by cyclization. For the intramolecular FCA reaction of secondary alcohols, which are the starting compounds (1a−1t), organic Bro̷ nsted acids, which require more innovative, easier, and suitable reaction conditions, were used instead of halide reagents with corrosive effects as classical FCA catalysts. Trifluoroacetic acid was determined to be the organocatalyst with the best yield. Therefore, some original 9-aryl/alkyl thioxanthene derivatives (2a−2t) were synthesized using the optimized FCA method. In addition, a new sulfone derivative of thioxanthene 3i was prepared by performing the oxidation reaction with one of the obtained new thioxanthene 2i. Thioxanthenes and their derivatives are important heterocyclic structures that contain pharmacologically valuable sulfur and are used in the treatment of psychotic diseases such as Alzheimer's or schizophrenia, as well as a number of potent biological activities.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Deniz,

Yıldız,

Başpınar Küçük

2024

ACS Omega

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“…Here, it was developed an optimized procedure of the Stetter reaction using some ortho -(thio)arenoxy benzaldehyde compounds ( 1a – 1n ) synthesized by us − and methyl vinyl ketone. We tried some NHC catalysts (Scheme ) in order to obtain a series of original ortho -(thio)arenoxy-substituted 1,4-diketone compounds ( 2a – 2n ), and 3-benzyl-5-(2-hydroxyethyl)-4-methylthiazolium chloride ( 3b ) was found as the best NHC catalyst.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Novel 1,4-Diketone Derivatives and Their Further Cyclization

et al. 2023

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One of the important reactions to obtain a new carbon−carbon bond is the Stetter reaction, which is generally via a nucleophilic catalyst like cyanide or thiazolium-NHC catalysts. In particular, 1,4-diketones with very functional properties are obtained by the Stetter reaction with the intermolecular reaction of an aldehyde and an α,β-unsaturated ketone. In this study, we synthesized new derivatives (substituted arenoxy) of 1,4-diketone compounds (2a−2n) with useful features by a new version of the Stetter reaction method. In our work, arenoxy benzaldehyde derivatives with different structures as the Michael donor and methyl vinyl ketone as the Michael acceptor were used for the intermolecular Stetter reaction. The reaction was catalyzed by 3benzyl-5-(2-hydroxyethyl)-4-methylthiazolium chloride (3b), using triethylamine for the basic medium and dimethyl sulfoxide as the solvent. As a result, some novel arenoxy-substituted 1,4-diketones were gained with good yields at room temperature within 24 h through an intermolecular Stetter reaction. In addition, new furan and pyrrole derivatives were prepared by performing the cyclization reaction with one of the obtained new diketone compounds.

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“…After these developments, the intramolecular FCA method using π-activated alcohols has frequently been used for xanthene synthesis. Some of these methods are the stereoselective synthesis of 9-vinyl-substituted unsymmetrical xanthenes and thioxanthenes by intramolecular FCA reaction [ 39 ], Lewis acid-catalyzed intramolecular FCA [ 40 ], and the synthesis of xanthenes and thioxanthenes by intramolecular FCA catalyzed with organic Brønsted superacid, which are our works [ 41 – 42 ]. According to the literature, there are also hydroarylation methods with FCA, which are made by unactivated alkenes instead of π-activated alcohols.…”

Section: Introductionmentioning

confidence: 99%

“…As a continuation of our series of works to develop organic Brønsted acid-catalyzed cyclization reactions [ 41 – 42 ], herein we report a highly efficient intramolecular FCA of appropriate unactivated alkenes with a polyaromatic structure in order to synthesize xanthene derivatives. We developed a new intramolecular FCA method by activating alkenes working under mild reaction conditions and have widened the substrate scope of alkenes to those containing varied electronic and steric properties.…”

Section: Introductionmentioning

confidence: 99%

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

Yıldız¹,

Baştaş²,

Küçük³

2021

Beilstein J. Org. Chem.

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In this work, new derivatives (substituted 9-methyl-9-arylxanthenes) of xanthene compounds (5a–l) of possible biological significance were synthesized by developing a new synthesis method. In order to obtain xanthene derivatives, the original alkene compounds to be used as the starting materials were synthesized in four steps using appropriate reactions. A cyclization reaction by intramolecular Friedel–Crafts alkylation was carried out in order to synthesize the desired xanthene derivatives using the alkenes as starting compounds. The intramolecular Friedel–Crafts reaction was catalyzed by trifluoroacetic acid (TFA) and provided some novel substituted 9-methyl-9-arylxanthenes with good yields at room temperature within 6–24 hours. As a result, an alkene compound was used for activation with TFA in the synthesis of xanthene through intramolecular Friedel–Crafts alkylation for the first time.

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Synthesis of new thioxanthenes by organocatalytic intramolecular Friedel–Crafts reaction

Cited by 11 publications

References 31 publications

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Intramolecular Friedel–Crafts Reaction with Trifluoroacetic Acid: Synthesizing Some New Functionalized 9-Aryl/Alkyl Thioxanthenes

Synthesis of Novel 1,4-Diketone Derivatives and Their Further Cyclization

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

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