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D. C. Gautam - One of the best experts on this subject based on the ideXlab platform.
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An Efficient Synthesis and Antimicrobial Studies of Bioactive 4H-1,4-Benzothiazine and Their Sulfone Derivatives
Phosphorus Sulfur and Silicon and the Related Elements, 2013Co-Authors: Naveen Gautam, Yogesh Dixit, Rahul Dixit, Sudesh Kumar Gupta, D. C. GautamAbstract:Abstract 4H-1,4-Benzothiazines were prepared by condensation followed by oxidative cyclization of substituted 2-aminobenzenethiols with β-diketones in dimethylsulfoxide. On refluxing with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-Benzothiazines yielded 4H-1,4-benzothiazine-1,1-dioxides. Structural evaluation has been done by spectral and elemental analysis. All the synthesized compounds were evaluated for their antibacterial and antifungal activity and all these have shown moderate to high activity against the test microbes. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text, figures and tables.
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An efficient synthesis and biological study of substituted 8-chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines, their sulphones and ribofuranosides
Journal of Chemical Sciences, 2013Co-Authors: Nishidha Khandelwal, Naveen Gautam, Abhilasha, D. C. GautamAbstract:8-Chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines were synthesized by condensation followed by oxidative cyclisation of 2-amino-6-chloro-3-methoxy/2-amino-3-chlorobenzenethiol with β–diketones/β–ketoesters in the presence of dimethyl sulphoxide. By treating 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-benzothiazine-1,1-dioxides (sulphones) were synthesized. The 4H-1,4-Benzothiazines have also been used as a base to prepare ribofuranosides by the reaction with β–D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antimicrobial and anthelmintic activity.
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an efficient synthesis and biological study of substituted 8 chloro 5 methoxy 8 chloro 4h 1 4 Benzothiazines their sulphones and ribofuranosides
Journal of Chemical Sciences, 2013Co-Authors: Nishidha Khandelwal, Naveen Gautam, D. C. GautamAbstract:8-Chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines were synthesized by condensation followed by oxidative cyclisation of 2-amino-6-chloro-3-methoxy/2-amino-3-chlorobenzenethiol with β–diketones/β–ketoesters in the presence of dimethyl sulphoxide. By treating 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-benzothiazine-1,1-dioxides (sulphones) were synthesized. The 4H-1,4-Benzothiazines have also been used as a base to prepare ribofuranosides by the reaction with β–D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antimicrobial and anthelmintic activity.
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Synthesis And Biological Activity Of Substituted 4H-1,4-Benzothiazines, Their Sulfones, And Ribofuranosides
Nucleosides nucleotides & nucleic acids, 2013Co-Authors: Kshamta Goyal, Naveen Gautam, Nishidha Khandelwal, D. C. GautamAbstract:The present article describes the synthesis of new 4H-1,4-Benzothiazines via condensation and oxidative cyclization of substituted 2-aminobenzenethiols with β-diketones/β-ketoesters in dimethyl sulfoxide. The oxidation of these synthesized 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid yielded 4H-1,4-benzothiazine sulfones and the reaction of these synthesized Benzothiazines with sugar (β-D-ribofuranose-1-acetate-2,3,5-tribenzoate) afforded the new ribofuranosides. These compounds were evaluated for their antioxidant and antimicrobial activities (using broth microdilution method). The structural assignments of the synthesized compounds were made on the basis of elemental analyses and spectroscopic data.
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Synthesis, Characterization and Pharmacological Importance of Novel 4H-1,4- Benzothiazines and their Sulfone Analogues
2013Co-Authors: Shikha Agarwal, Naveen Gautam, Neha Ajmera, Neetu Kumari, Dinesh K. Agarwal, Sudesh Gupta, D. C. GautamAbstract:H-1,4-Benzothiazines and its derivatives are potential pharmacologically and industrially useful agents. They were prepared by condensation followed by oxidative cyclization of 2-amino-4,6-dimethylbenzenethiol with varied β- diketones/β-ketoesters in dimethyl sulfoxide. On refluxing with H2O2 in glacial acetic acid, the substituted 4H-1,4- Benzothiazines yielded 4H-1,4-Benzothiazine-1,1-dioxides (sulfones). These compounds were evaluated for antioxidant activity by DPPH and ABTS assay and the antimicrobial properties were investigated against various strains of bacteria (Coagulase negative Staphylococci, Coagulase positive Staphylococci, Enterobacter) and fungi (Candida albicans) using Paper disc method. The structures of the compounds have been confirmed by spectral and elemental analysis.
R R Gupta - One of the best experts on this subject based on the ideXlab platform.
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synthesis of sulfones of 4h 1 4 Benzothiazines and phenothiazines
Phosphorus Sulfur and Silicon and The Related Elements, 2004Co-Authors: Gulshan Kumar, D. C. Gautam, Vandana Gupta, R R GuptaAbstract:Conversion of 5/7-chloro-4H-1,4-Benzothiazines and 1/3-chlorophenothiazines into sulfones is reported. The 5/7-chloro-4H-1,4-Benzothiazines were synthesized by the condensation and oxidative cyclization of 2-amino 3/5-chlorobenzenethiol with β diketones in DMSO. The phenothiazines have been synthesized via Smiles rearrangement by the reaction of 2-amino-3/5-chlorobenzenethiol with halonitrobenzenes. 4H-1,4-Benzothiazine and phenothiazine sulfones have been prepared by the oxidation of Benzothiazines and phenothiazines with 30% hydrogen peroxide in glacial acetic acid. The structure of all the synthesized compounds has been confirmed by IR and NMR spectral studies.
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Synthesis of 7-Bromo/5,6-Dimethyl-4 H -1,4-Benzothiazines and Their Conversion into Sulfones
Phosphorus Sulfur and Silicon and the Related Elements, 2003Co-Authors: P. R. Sharma, D. C. Gautam, Vandana Gupta, R R GuptaAbstract:The synthesis of 7-bromo/5,6-dimethyl-4 H -1,4-Benzothiazines and their conversion into sulfones is reported. The 7-bromo/5,6-dimethyl-4 H -1,4-Benzothiazines were synthesized by the condensation and oxidative cyclization of 2-amino-5-bromo/3,4-dimethylbenzenethiol with g -diketones in dimethyl sulfoxide. The reaction is believed to proceed via an enaminoketone system. 4 H -1,4-Benzothiazine sulfones have been synthesized by the oxidation of 4 H -1,4-Benzothiazines using 30% H 2 O 2 in glacial acetic acid. The structures of all newly synthesized compounds have been confirmed by elemental analysis and spectral studies.
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Synthetic and spectral investigations of fluorinated 4H-1,4-Benzothiazines and their conversion into sulfones
Journal of Fluorine Chemistry, 1999Co-Authors: M.y. Hamadi, Rajni Gupta, R R GuptaAbstract:Abstract The synthesis of fluorinated 4 H -1,4-Benzothiazines and their conversion into sulfones is reported. The fluorinated 4 H -1,4-Benzothiazines were prepared by the condensation and oxidative cyclization of 2-amino-3-chloro-5-fluorobenzenethiol with compounds containing active methylene groups in DMSO. The reaction is believed to proceed via an enaminoketone system. Fluorinated 4 H -1,4-benzothiazine sulfones have been synthesized by the oxidation of fluorinated 4 H -1,4-Benzothiazines by 30% hydrogen peroxide in glacial acetic acid. IR, NMR and mass spectral investigations are included.
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synthetic and spectral investigation of fluorinated phenothiazines and 4h 1 4 Benzothiazines as potent anticancer agents
Journal of Fluorine Chemistry, 1993Co-Authors: R R Gupta, Madhu Jain, R S Rathore, Archana GuptaAbstract:Abstract The syntheses of fluorinated phenothiazines and fluorinated 1,4-Benzothiazines are reported.Fluorinated phenothiazines have been prepared via a Smiles rearrangement of N-formylateddiphenylsulphides, synthesized in turn by condensation of substituted 2-aminobenzenethiolswith 2-chloro-5-trifluoromethylnitrobenzene followed by formylation with formic acid.Fluorinated 4H-1,4-Benzothiazines have been prepared by the condensation and oxidativecyclization of substituted 2-aminobenzenethiols with p-fluorobenzoylacetone in DMSO.The reaction is believed to proceed via an enaminoketone system. IR and NMR spectralinvestigations are included.
Emmanuel Magnier - One of the best experts on this subject based on the ideXlab platform.
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Divergent Synthesis of 1,2-Benzo[ e ]thiazine and Benzo[ d ]thiazole Analogues Containing a S -Trifluoromethyl Sulfoximine Group: Preparation and New Properties of the Adachi Reagent
Journal of Organic Chemistry, 2019Co-Authors: Anne-laure Barthelemy, Elsa Anselmi, Giang Vo-thanh, Régis Guillot, Karinne Miqueu, Emmanuel MagnierAbstract:We report here the preparation of unprecedented analogues of 1,2-benzothiazine and benzoisothiazoleincorporating theS-trifluoromethyl sulfoximine group in their core. Using a stable precursor to start, cyclization occurs via acatalytic controlled process. The choice of the catalyst is crucial for selectivity toward thefive- or the six-membered ring.Interestingly, one of the Benzothiazines can be converted on a gram scale into the trifluoromethylating Adachi reagent. We alsodisclose thefirst use of this reagent as a source of radical CF3under photoredox catalysis. DFT calculations were performed toclarify the cyclization mechanism.
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Divergent Synthesis of 1,2-Benzo[e]thiazine and Benzo[d]thiazole Analogues Containing a S‑Trifluoromethyl Sulfoximine Group: Preparation and New Properties of the Adachi Reagent
2019Co-Authors: Anne-laure Barthelemy, Elsa Anselmi, Giang Vo-thanh, Karinne Miqueu, Régis Guillot, Emmanuel MagnierAbstract:We report here the preparation of unprecedented analogues of 1,2-benzothiazine and benzoisothiazole incorporating the S-trifluoromethyl sulfoximine group in their core. Using a stable precursor to start, cyclization occurs via a catalytic controlled process. The choice of the catalyst is crucial for selectivity toward the five- or the six-membered ring. Interestingly, one of the Benzothiazines can be converted on a gram scale into the trifluoromethylating Adachi reagent. We also disclose the first use of this reagent as a source of radical CF3 under photoredox catalysis. DFT calculations were performed to clarify the cyclization mechanism
Naveen Gautam - One of the best experts on this subject based on the ideXlab platform.
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An Efficient Synthesis and Antimicrobial Studies of Bioactive 4H-1,4-Benzothiazine and Their Sulfone Derivatives
Phosphorus Sulfur and Silicon and the Related Elements, 2013Co-Authors: Naveen Gautam, Yogesh Dixit, Rahul Dixit, Sudesh Kumar Gupta, D. C. GautamAbstract:Abstract 4H-1,4-Benzothiazines were prepared by condensation followed by oxidative cyclization of substituted 2-aminobenzenethiols with β-diketones in dimethylsulfoxide. On refluxing with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-Benzothiazines yielded 4H-1,4-benzothiazine-1,1-dioxides. Structural evaluation has been done by spectral and elemental analysis. All the synthesized compounds were evaluated for their antibacterial and antifungal activity and all these have shown moderate to high activity against the test microbes. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text, figures and tables.
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An efficient synthesis and biological study of substituted 8-chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines, their sulphones and ribofuranosides
Journal of Chemical Sciences, 2013Co-Authors: Nishidha Khandelwal, Naveen Gautam, Abhilasha, D. C. GautamAbstract:8-Chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines were synthesized by condensation followed by oxidative cyclisation of 2-amino-6-chloro-3-methoxy/2-amino-3-chlorobenzenethiol with β–diketones/β–ketoesters in the presence of dimethyl sulphoxide. By treating 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-benzothiazine-1,1-dioxides (sulphones) were synthesized. The 4H-1,4-Benzothiazines have also been used as a base to prepare ribofuranosides by the reaction with β–D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antimicrobial and anthelmintic activity.
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an efficient synthesis and biological study of substituted 8 chloro 5 methoxy 8 chloro 4h 1 4 Benzothiazines their sulphones and ribofuranosides
Journal of Chemical Sciences, 2013Co-Authors: Nishidha Khandelwal, Naveen Gautam, D. C. GautamAbstract:8-Chloro-5-methoxy/8-chloro-4H-1,4-Benzothiazines were synthesized by condensation followed by oxidative cyclisation of 2-amino-6-chloro-3-methoxy/2-amino-3-chlorobenzenethiol with β–diketones/β–ketoesters in the presence of dimethyl sulphoxide. By treating 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid, 4H-1,4-benzothiazine-1,1-dioxides (sulphones) were synthesized. The 4H-1,4-Benzothiazines have also been used as a base to prepare ribofuranosides by the reaction with β–D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antimicrobial and anthelmintic activity.
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Synthesis And Biological Activity Of Substituted 4H-1,4-Benzothiazines, Their Sulfones, And Ribofuranosides
Nucleosides nucleotides & nucleic acids, 2013Co-Authors: Kshamta Goyal, Naveen Gautam, Nishidha Khandelwal, D. C. GautamAbstract:The present article describes the synthesis of new 4H-1,4-Benzothiazines via condensation and oxidative cyclization of substituted 2-aminobenzenethiols with β-diketones/β-ketoesters in dimethyl sulfoxide. The oxidation of these synthesized 4H-1,4-Benzothiazines with 30% hydrogen peroxide in glacial acetic acid yielded 4H-1,4-benzothiazine sulfones and the reaction of these synthesized Benzothiazines with sugar (β-D-ribofuranose-1-acetate-2,3,5-tribenzoate) afforded the new ribofuranosides. These compounds were evaluated for their antioxidant and antimicrobial activities (using broth microdilution method). The structural assignments of the synthesized compounds were made on the basis of elemental analyses and spectroscopic data.
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Synthesis, Characterization and Pharmacological Importance of Novel 4H-1,4- Benzothiazines and their Sulfone Analogues
2013Co-Authors: Shikha Agarwal, Naveen Gautam, Neha Ajmera, Neetu Kumari, Dinesh K. Agarwal, Sudesh Gupta, D. C. GautamAbstract:H-1,4-Benzothiazines and its derivatives are potential pharmacologically and industrially useful agents. They were prepared by condensation followed by oxidative cyclization of 2-amino-4,6-dimethylbenzenethiol with varied β- diketones/β-ketoesters in dimethyl sulfoxide. On refluxing with H2O2 in glacial acetic acid, the substituted 4H-1,4- Benzothiazines yielded 4H-1,4-Benzothiazine-1,1-dioxides (sulfones). These compounds were evaluated for antioxidant activity by DPPH and ABTS assay and the antimicrobial properties were investigated against various strains of bacteria (Coagulase negative Staphylococci, Coagulase positive Staphylococci, Enterobacter) and fungi (Candida albicans) using Paper disc method. The structures of the compounds have been confirmed by spectral and elemental analysis.
Michael Harmata - One of the best experts on this subject based on the ideXlab platform.
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preparation of s 2 halophenyl 2 1 Benzothiazines
Tetrahedron, 2021Co-Authors: Aswin Garimalla, Michael HarmataAbstract:ABSTRACT Derivatives of 2,1-Benzothiazines are useful synthetic intermediates for a variety of applications. We became interested in developing a one-pot procedure to S-2-halophenyl-2,1-Benzothiazines as potential precursors to P,N type ligands for metals. Accordingly, we reacted S-2-halophenyl-S-methylsulfoximines with 2-bromobenzaldehydes using the Buchwald-Hartwig reaction under conditions previously developed in our laboratory. We found that 2-halophenylmethyl sulfoximines show lower reactivity in process than methylphenyl sulfoximine. Among the 2-(S)-2-halophenyl-(S)-methylsulfoximines tested, S-2-fluorophenyl-S-methyl sulfoximine was found to afford higher yields of Benzothiazines than the bromine- or chlorine-substituted congeners. In the coupling of S-2-halophenyl-S-methylsulfoximines to 2-bromobenzaldehyde, using Ruphos as a ligand gave the best yields.
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Formation of a benzothiazine via the reaction of ortho-halo sulfoximines with copper salts
Arkivoc, 2012Co-Authors: Aswinkumar Garimallaprabhakaran, Xuechuan Hong, Michael HarmataAbstract:The formation of an interesting benzothiazine from the reaction of S-(o-halophenyl)-S-methyl sulfoximines in the presence of copper salts is reported. The overall yield is 27% over three steps from commercially available 2-halothioanisoles in the best case. The product’s structure was confirmed by spectroscopic and X-ray crystal analysis. The benzothiazine shows fluorescent properties.
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Benzothiazines in organic synthesis. Synthesis of fluorescent 7-amino-2,1-Benzothiazines
Organic & biomolecular chemistry, 2011Co-Authors: Nattawut Yongpruksa, Siddharth Pandey, Gary A. Baker, Michael HarmataAbstract:Fluorescent 7-amino-2,1-Benzothiazines were prepared in high yields using the palladium-catalyzed reaction of 4-amino-2-chlorobenzaldehydes with a sulfoximine or the reaction of 7-fluoro-2,1-Benzothiazines with amines.
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Benzothiazines in synthesis further studies of the intramolecular stereoselective addition of sulfonimidoyl carbanions to α β unsaturated functional groups
Journal of Organic Chemistry, 2009Co-Authors: Michael Harmata, Kanokon Rayanil, Vinson R Espejo, C L BarnesAbstract:A variety of alkenes substituted by electron-withdrawing groups serve as competent electrophiles for the stereoselective, intramolecular nucleophilic addition of sulfonimidoyl carbanions to form Benzothiazines. This reaction generally proceeds with complete stereoselectivity within the limits of our detection. In some cases, benzothiazine formation occurs in a single pot at relatively high temperatures during N-arylation of the simple sulfoximine used in this study. Yet, the process occurs with the same direction and extent of stereoselectivity as that seen when the Michael addition is performed at very low temperatures.
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New chiral benzothiazine ligand and its use in the synthesis of a chiral receptor.
The Journal of organic chemistry, 2006Co-Authors: Michael Harmata, Nathan L. Calkins, Russell G. Baughman, Charles L. BarnesAbstract:The development of chiral ligands to direct the course and stereoselectivity of many catalytic asymmetric reactions is an important area of interest for many research groups. As part of a program examining the chemistry of 2,1-Benzothiazines, we have prepared a new chiral benzothiazine ligand. This ligand can be made in as few as three steps from commercially available starting materials. Presented herein is the synthesis of the ligand along with the synthesis of a chiral molecular receptor that potentially presages a new class of chiral molecular tweezers.