D. C. Gautam

Synthesis and Antimicrobial Activities of Novel Biologically Active Heterocycles: 10H-Phenothiazines, Their Ribofuranosides, and Sulfone Derivatives

This article deals with the synthesis and antimicrobial activity of a series of novel substituted 10H-phenothiazines, their ribofuranosides, and sulfone derivatives. 10H-Phenothiazines were prepared by Smiles rearrangement. These prepared phenothiazines were used as the base to prepare ribofuranosides by treatment with sugar (1-O-acetyl-2,3,5-tri-O-benzoylribofuranose). Sulfone derivatives were prepared by the oxidation of 10H-phenothiazines. The structure of the synthesized compounds was established by elemental analysis and spectroscopic data.

Synthesis of Some Substituted 10H-Phenothiazines, Ribofuranosides, and their Antioxidant Activity

10H-substituted phenothiazines were prepared by Smiles rearrangement. These prepared phenothiazines were used as base to prepare ribofuranosides by treatment with sugar. Their antioxidant activity was carried out. The structure of both 10H-Phenothiazines and ribofuranosides was established by spectroscopic data and optical rotation data.

Synthesis and Biological Activities of Some New Phenothiazines, Their Sulfones, and Ribofuranosides

The present communication describes the synthesis of substituted 10H-phenothiazines by reaction of 2-aminobenzenethiol 1 and o-halonitrobenzene 2 via Smiles rearrangement. These synthesized phenothiazines are used as base to prepare ribofuranosides by treatment with sugar viz. β -D-ribofuranosyl-1-acetate-2,3,5-tribenzoate. Sulfones are also synthesized by oxidation of 10H-phenothiazines refluxing with H2O2 in glacial acetic acid. All synthesized compounds have been characterized by IR, 1 H NMR, 13 C NMR Mass spectra and elemental analysis and screened for antioxidant and antimicrobial activity.

Synthesis of 7-Bromo/5,6-Dimethyl-4 H -1,4-Benzothiazines and Their Conversion into Sulfones

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.

Synthesis of 4H-1,4-Benzothiazine-1,1-dioxides (Sulfones) and Phenothiazine-5,5-dioxides (Sulfones)

The study of the oxidation behavior of 4H-1,4-benzothiazines and phenothiazines by 30% hydrogen peroxide in acetic acid results in the formation of 4H-1,4-benzothiazine-1,1-dioxides (sulfones) and 10H-phenothiazine-5,5-dioxides (sulfones) respectively. The purity of all the synthesized compounds has been checked by thin layer chromatography using silica “G” as an adsorbent in various nonaqueous solvent systems. Infra-red and proton-magnetic resonance spectral studies are also included.

An Efficient Synthesis and Antimicrobial Studies of Bioactive 4H-1,4-Benzothiazine and Their Sulfone Derivatives

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 publishers online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text, figures and tables. GRAPHICAL ABSTRACT

Synthetic Methodology, Spectral Elucidation, and Antioxidative Properties of Benzothianes and Their Sulfones

This article reflects the synthetic strategies and spectral investigation of 4H-1,4-benzothiazines. 4H-1,4-benzothiazines have been prepared by the condensation and oxidative cyclization of substituted 2-aminobenzenethiol with β-diketones/β-ketoesters in dimethyl sulfoxide and with the oxidation of 4H-1,4-benzothiazines by 30% hydrogen peroxide in glacial acetic acid, which results in the formation of 4H-1,4-benzothiazine sulfones. The compounds were evaluated for their antioxidative properties through in vitro and in vivo studies in Swiss albino mice. The structural assignments of compounds were made on the basis of spectroscopic data and elemental analysis.

Synthesis And Biological Activity Of Substituted 4H-1,4-Benzothiazines, Their Sulfones, And Ribofuranosides

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.

An efficient synthesis and biological study of substituted 8-chloro-5-methoxy/8-chloro-4H-1,4-benzothiazines, their sulphones and ribofuranosides

Abstract8-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. Graphical Abstract4H-1,4-benzothiazines, the nitrogen and sulphur containing heterocycles are prepared by condensation followed by oxidative cyclization of 2-aminobenzenethiols with β-diketones/β-ketoester in dimethylsulphoxide. These compounds were then used as base to prepare ribofuranosides and their sulphones.

Synthesis of Bioactive Fluorinated 10H-Phenothiazines and their Sulfone Derivatives

The present communication deals with the synthesis of a series of fluorinated 10H-phenothiazines. 10H-phenothiazines is prepared by Smiles rearrangement of substituted 2-foramido-2´-nitrodiphenylsulfide. Substituted 2-foramido-2´-nitrodiphenylsulfide were obtained by the reaction of 2-amino-3-fluorobenzenethiol with o-halonitrobenzenes followed by formylation and 1-nitro/1-halo-10H-phenothiazines have been prepared by the reaction of substituted 2-aminobenzenethiols with reactive o-halonitrobenzene containing a nitro group or halogen atom at o-position to the reactive halogen atom directly yielded 1-nitro/1-halo-10H-phenothiazines in situ. 10H-phenothiazine sulfone derivatives have been synthesized by the oxidation of 10H-phenothiazines by 30% hydrogen peroxide in glacial acetic acid. The structure of the synthesized compounds has been characterized by spectroscopic data and elemental analysis. Antimicrobial studies of the synthesized compounds have also been included.