A Tandem Michael–S<sub>N</sub>2‐Mediated General Route to Six‐Membered Heterocycles and Carbocycles

Atta, Ananta Kumar; Pathak, Tanmaya

doi:10.1002/ejoc.201000941

Cited by 13 publications

(8 citation statements)

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“…Since its inception by Swedish chemists in 1940, the Ramberg–Bäcklund rearrangement (RBR) has endured as a classic carbon–carbon bond forming reaction used time and time again through the modern history of organic synthesis. , The rearrangement has been applied in the synthesis of important organic building blocks, − natural products and several stilbenoid anticancer agents. − The RBR is the base promoted conversion of an α-halosulfone into an episulfone followed by the loss of SO 2 to give an alkene through connection of the sulfone’s two α-carbons. (Scheme ) .…”

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confidence: 99%

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

Söderman

Schwan

2012

J. Org. Chem.

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confidence: 99%

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

Söderman

Schwan

2012

J. Org. Chem.

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“…In 2010, another type of asymmetric domino Michael-intramolecular alkylation reaction was developed by Pathak et al to achieve a range of chiral six-membered heterocycles and carbocycles bearing three contiguous stereocentres. 23 In this case, the domino reaction occurred between a chiral vinyl sulfone derived from ribose and Na 2 S, which provided the corresponding enantiopure cyclic sulfide in 72% yield, as shown in Scheme 1.12. This highly efficient methodology was applied to a series of other nucleophiles, such as primary amines and dialkyl malonates, leading to the corresponding piperidine derivatives and cyclohexane derivatives, respectively.…”

Section: Domino Reactions Initiated By the Michael Reactionmentioning

confidence: 97%

Asymmetric Domino Reactions Based on the Use of Chiral Substrates

2013

Asymmetric Domino Reactions

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This chapter updates the recent developments in asymmetric one-, two-, and multicomponent domino reactions which involve chiral substrates. It is divided into two sections, dealing successively with one- and two-component domino reactions, and with multicomponent domino reactions. The first section is subdivided into eight sections, describing domino reactions with an anionic primary step, domino reactions based on cationic sequences, domino reactions initiated by a pericyclic primary step, domino reactions based on carbene sequences, palladium-catalysed domino reactions, ruthenium-catalysed domino reactions, gold-catalysed domino reactions, and finally miscellaneous domino reactions. The second section of the chapter is subdivided into 10 sections, dealing with multicomponent reactions initiated by the Michael addition, multicomponent reactions based on the Hantzsch reaction, multicomponent reactions based on the Ugi reaction, multicomponent reactions based on the Strecker reaction, multicomponent reactions based on the Mannich reaction, multicomponent reactions initiated by an allylation reaction, multicomponent reactions based on the Passerini reaction, multicomponent reactions based on the Biginelli reaction, multicomponent reactions based on the Petasis reaction, and finally miscellaneous multicomponent reactions. The power and utility of these reactions are well illustrated by their application in the synthesis of a wide range of structurally diverse and complex chiral molecules.

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“…Moreover, they show a marked increase in in vitro activity against Grampositive bacteria [5] and cancer [6]. These are used as key starting materials due to their high electrophilicity, where the β-aroyl acrylic acids react readily with nucleophiles, including nitrogen and sulfur nucleophiles, to afford either cyclic or normal Michael adducts depending on the nature of the attacking nucleophiles and the reaction medium (neutral, basic, acidic) and the Michael addition reaction may be utilized in tandem as efficient strategy for the construction of ring structures [7][8][9]. Therefore, this starting material has been used to prepare more interesting heterocyclic 1,5-benzothiazepine compounds having a substituent in the fused benzene ring, which may have diverse biological activities.…”

Section: Introductionmentioning

confidence: 99%

Syntheses of 1,5-Benzothiazepines: Part 48: Single Pot Syntheses and Antimicrobial Studies of 8-Substituted 4-(2,4/2,5-disubstituted aryl)-2,3-dihydro-1,5-benzothiazepine-2-carboxylic Acids

Pant¹,

Yadav²

2017

Asian J. Chem.

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Two substituted acrylic acids, β-(2,4-dimethylbenzoyl) acrylic acid and β-(2,5-diisopropylbenzoyl) acrylic acid were reacted with six 5-substituted 2-aminobenzenethiols, in dry ethanol containing trifluroacetic acid to obtain ten new compounds, 8-substituted 4-(2,4-dimethylphenyl/2,5-diisopropylphenyl)-2,3-dihydro-1,5-benzothiazepine-2-carboxylic acids in 53-63 % yields. The products were characterized on the basis of micro analytical data and spectral analysis comprising IR, 1 H NMR and mass studies. All the synthesized compounds have been screened for their antimicrobial activity against the Gram-positive bacteria, Staphylococcus aureus and Gramnegative bacteria, Enterobacter cloacae, Klebsiella aerogenes and fungus, Candida albicans with respective reference compounds. Keywords: Acrylic acids, 5-Substituted 2-aminobenzenethiols, Antimicrobial activity.Asian Journal of Chemistry; Vol. 29, No. 10 (2017), 2221-2223 containing trifluoroacetic acid to obtain the final compounds in single step in 53-63 % yields. The purity of the final products was checked by TLC. The structures of the final products were ascertained by elemental and spectral analyses comprising IR, 1 H NMR and mass spectral studies. All the compounds 3a-l were evaluated for their antimicrobial activity, comprising antibacterial and antifungal.General procedure for the syntheses of 8-substituted 4-(2,4-dimethylphenyl/2,5-diisopropylphenyl)-2,3-dihydro-1,5-benzothiazepine-2-carboxylic acids (3a-l): To a solution of β-(2,4-dimethylbenzoyl/2,5-diisopropylbenzoyl) acrylic acid (1, 0.001 mol) in dry ethanol (5 mL) containing trifluoroacetic acid, was added the ethanolic solution of 5-substituted 2-aminobenzenethiols (2, 0.001mol) with continuous stirring. The reaction mixture after refluxing for 3-4 h followed by cooling, afforded the crude, which was filtered and crystallized from ethanol to give coloured crystals of the target compounds (3a-l).Antimicrobial activity: The antimicrobial activity of all newly synthesized compounds 8-substituted 2,3-dihydro-4-(2,4-dimethylphenyl/2,5-diisopropylphenyl)-1,5-benzothiazepine-2-carboxylic acids (3a-l), were carried out using paper disc method [11] against the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Enterobacter cloacae, Klebsiella aerogenes and antifungal activity against the fungus, Candida albicans at the concentration of 200 µg/disc, with vancomycin and polymixin B and fluconazole as the reference drugs, respectively. The reference compounds were used to evaluate the activity in the form of activityScheme-I index. Zones of inhibition, exhibited by the reference and test compounds, were measured and compared to show relative activities in the form of activity index. The physical constants and the antimicrobial activity is given in Table-1. Detection method: All the reported melting points are uncorrected. Purity of the compounds were checked by TLC on glass plates coated with silica gel 'G' as absorbent, using benzene : ethanol : aq. ammonia (50 %) in the ratio 7:2:1 as so...

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A Tandem Michael–S_N2‐Mediated General Route to Six‐Membered Heterocycles and Carbocycles

Abstract: A powerful, flexible, and stereoselective general strategy for the construction of chirally pure six-membered heterocycles and carbocycles by utilizing a tandem Michael-S N 2 sequence is described. The strategy avoids the tedious synthe-

Cited by 13 publications

References 46 publications

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

Asymmetric Domino Reactions Based on the Use of Chiral Substrates

Syntheses of 1,5-Benzothiazepines: Part 48: Single Pot Syntheses and Antimicrobial Studies of 8-Substituted 4-(2,4/2,5-disubstituted aryl)-2,3-dihydro-1,5-benzothiazepine-2-carboxylic Acids

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A Tandem Michael–SN2‐Mediated General Route to Six‐Membered Heterocycles and Carbocycles

Abstract: A powerful, flexible, and stereoselective general strategy for the construction of chirally pure six-membered heterocycles and carbocycles by utilizing a tandem Michael-S N 2 sequence is described. The strategy avoids the tedious synthe-

Cited by 13 publications

References 46 publications

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

1,2-Dibromotetrachloroethane: An Ozone-Friendly Reagent for the in Situ Ramberg–Bäcklund Rearrangement and Its Use in the Formal Synthesis of E-Resveratrol

Asymmetric Domino Reactions Based on the Use of Chiral Substrates

Syntheses of 1,5-Benzothiazepines: Part 48: Single Pot Syntheses and Antimicrobial Studies of 8-Substituted 4-(2,4/2,5-disubstituted aryl)-2,3-dihydro-1,5-benzothiazepine-2-carboxylic Acids

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A Tandem Michael–S_N2‐Mediated General Route to Six‐Membered Heterocycles and Carbocycles