Synthesis and antimicrobial activity of structurally flexible heterocycles with the 1,4-thiazine heterosystem

A Bioinspired Synthesis of 1,4-Benzothiazines by Selective Addition of Sulfur Nucleophiles to ortho-Quinones

Herein, we report a bioinspired approach to the synthesis of 1,4-benzothiazines by drawing inspiration from the biosynthesis of pheomelanin pigments (pheomelanogenesis). In this context, general conditions for the regioselective coupling reaction between ortho-quinones and thiols were developed. The mild conditions proved amenable to a wide scope of both thiol and ortho-quinone coupling partners while simultaneously suppressing redox-exchange. The utility of this methodology was demonstrated by a synthesis of 1,4-benzothiazines, following a biomimetic, oxidative cyclization.

A Review on Medicinally Important Heterocyclic Compounds

Heterocyclic compounds account for the most prominent and diverse class of organic compounds. A significant number of heterocyclic compounds have been synthesized up to this point. Heterocyclic compounds are rapidly increasing in number due to extensive synthetic research and also their synthetic utility. Such compounds have a wide range of uses in the field of medicinal chemistry. Dyestuff, sanitizers, corrosion inhibitors, antioxidants, and copolymer synthesis are additional well-known applications. There are always distinguishing characteristics of an efficient approach for producing newly discovered heterocyclic compounds and their moieties. According to prior research, more than 90% of medicines containing heterocyclic compounds have been developed after the obtainment of a thorough scientific grasp of the biological system. It was discovered in the neoteric developments of heterocyclic compounds that these play a vital role in curative chemistry, and exert anticancer, anti-inflammatory, antifungal, antiallergic, antibacterial, anti-HIV, antiviral, anti-convulsant, and other biological activities. The present article provides detailed information regarding such heterocyclic compounds.

Recent advances in the synthesis of benzothiazole and its derivatives

Abstract:

Benzothiazoles have recognized pharmacophores in the field of research, predominantly in synthetic and medicinal chemistry, on account of their significant pharmaceutical properties. This important class of derivatives endows an extensive range of biological activities like anti-inflammatory, antidiabetic, anticancer, anticonvulsant, antibacterial, antiviral, antioxidant, antituberculosis, enzyme inhibitors, etc. Hence, various methodologies have been accomplished to synthesize benzothiazole compounds considering the purity, yield, and selectivity of the products. This review provides different reaction methods that are involved in the synthesis of a variety of benzothiazole derivatives.

Three-component synthesis of 1,4-benzothiazines via iodide-catalyzed aerobic C–H sulfuration with elemental sulfur

Five to Six: Beyond the well-established thiazole formation from elemental sulfur, this method provides the first access to the corresponding six-membered N,S-heterocyclic products via direct functionalization of multiple C–H bonds.

Tunable Synthesis of Disulfide-Functionalized Enaminones and 1,4-Thiazines via the Reactions of Enaminones and β-Aminoethanethiol

The reactions of β-aminoethanethiol with N,N-dimethyl enaminones are performed to selectively provide disulfide-functionalized enaminones and 1,4-thiazines. By performing the reaction in water and catalyst-free conditions, the transamination and oxidative S-S coupling between the two substrates take place to give disulfide-functionalized enaminones. On the other hand, by using identical starting materials, the employment of the CuI catalyst in dimethyl sulfoxide enables the selective generation of 1,4-thiazines via tandem transamination and C(sp2)-H bond thiolation.

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 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.