Naveen 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.

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.

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.

Synthesis, characterization and in vitro antimicrobial assessment of some novel 4H-1, 4-benzothiazines and their sulfone derivatives

Abstract In recent years, synthesis and biological evaluation of novel 4H-1,4-benzothiazines and their sulfone derivatives have gained momentum due to their medicinal and industrial importance. Our studies focused on the design and synthesis of new antimicrobial agents, and for this purpose a series of novel 4H-1,4-benzothiazines and their sulfone derivatives were synthesized and their in vitro antimicrobial assessment was carried out against a representative panel of Gram-positive and Gram-negative bacteria strains and selected fungi species. The reported 4H-1,4-benzothiazines were prepared by condensation followed by oxidative cyclization of substituted 2-aminobenzenethiols with compounds containing active methylene groups. It is believed that the reaction proceeds via intermediary of the enaminoketone system. The sulfone derivatives were synthesized by oxidation of 4H-1,4-benzothiazines using 30% hydrogen peroxide in glacial acetic acid. Structure determination was done by spectral and elemental investigations.

Antioxidant and Antimicrobial Assessment of Synthesized and Spectrally Characterized New Nitrophenothiazines and their Sulfone Analogues

GRAPHICAL ABSTRACT Abstract A series of new nitrophenothiazines and their sulfones were synthesized and their in vitro antimicrobial assessment was carried out against a representative panel of gram positive and gram negative bacterial strains and selected fungi species. The synthesized compounds were screened for antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) radical cation decolorization assay. Structural determination was carried out by spectral and elemental investigations.

Synthesis, Spectral Characterization, and Pharmacological Importance of New 4H-1,4-Benzothiazines, Their Sulfone Analogues, and Ribofuranosides

The present article describes the synthesis of new 4H-1,4-benzothiazines via condensation and oxidative cyclization of substituted 2-aminobenzenethiols with compounds containing active methylene groups. It is believed that the reaction proceeds via intermediary of the enaminoketone system. The sulfone derivatives were synthesized by oxidation of 4H-1,4-benzothiazines using 30% hydrogen peroxide in glacial acetic acid. Benzothiazines were used as bases to prepare ribofuranosides by treatment with a sugar derivative (β-D-ribofuranosyl-1-acetate-2,3,5-tribenzoate). The pharmacological importance of the synthesized compounds was evaluated by their, antimicrobial properties against various bacterial strains and fungal species. The structures of the compounds have been confirmed by spectral and chemical analysis.

Synthesis and Antitubercular Screening of Some Novel 4H-1,4- Benzothiazines and their Sulfones Under Environment Benign Solvent Free Conditions as Future Anti-Tubercular Agents

Some novel analogs of 4H-1,4-benzothiazines were synthesized under environmentally benign solvent free conditions by one pot oxidative cyclocondensation of substituted 2- aminobenzenthiols with compounds having active methylene group and then converted in to sulfones. These compounds were examined as antitubercular agents against Mycobacterium tuberculosis H37Rv using REMA plate method. The best results have MICs from 6.4 to 8.8 μg/mL, comparable to phenothiazines. IR, NMR and mass spectral investigations are included for structural elucidation.