Current Perspective of Synthesis of Medicinally Relevant Benzothiazole Based Molecules: Potential for Antimicrobial and Anti-Inflammatory Activities

The therapeutic potential of the majority of the marketed drugs is due to the presence of a heterocyclic nucleus, which constitutes a huge role in the field of medicinal chemistry. These heterocyclic scaffolds could act as a template in order to design potential therapeutic agents against several diseases. Benzothiazole scaffold is one of the influential heteroaromatic rings in the field of medicinal chemistry owing to its extensive pharmacological features. Herein, we have focused on the synthesis of benzothiazole based medicinal molecules, which possess antimicrobial and anti-inflammatory activities. This review covers a systematic description of synthetic routes for biologically relevant benzothiazole derivatives in the last five years. The main aim of this study is to show the diversification of benzothiazole based molecules into their pharmacologically more active derivatives. This review's synthetic protocols include metal-free, metal-catalyzed, and metal precursor azo dyes strategies for the development of benzothiazole derived bioactive compounds. The discussion under the various headings covers synthetic schemes and biological activities of the most potent molecules in the form of minimum inhibitory concentration.

Lewis acid-promoted formation of benzoselenazole derivatives using SeO2 as a selenium source

A new one-pot method of using both ortho-inactivated anilines and acetophenones (or methylquinolines) which possess an active H in the α-position of ketones (or benzyl positions) as starting materials to make benzoselenazole derivatives has been developed, which uses SeO2 as a selenium agent. This method first establishes SeO2 as a source of selenium to form benzoselenazole derivatives, which enriches the synthesis method of benzoselenazole. This method has several advantages, including good yields, simple operation, and availability of raw materials. Furthermore, the reaction could be easily scaled and its practical value in organic synthesis is displayed.

Recent Advances in the Synthesis and Applications of 2-Arylbenzothiazoles

This review firstly covers the applications of 2-arylbenzothiazoles as amyloid imaging agents, antitumor agents, and organic luminescent materials. Then we review the recent advances in the synthesis of 2-arylbenzothiazole derivatives. On the one hand, we introduce the approaches for construction of the 2-arylbenzothiazole core, including the following categories: (i) classic condensation of 2-aminothiophenols, (ii) direct arylation of benzothiazoles, (iii) intramolecular cyclization of thiobenzanilides, and (iv) tandem cyclization of anilines/ nitroarenes­ with elemental sulfur or sulfides. On the other hand, the transition-metal-catalyzed direct C–H functionalizations of 2-aryl­benzothiazoles are also involved in this review.

1 Introduction

2 Applications of 2-Arylbenzothiazoles

3 Construction of the 2-Arylbenzothiazole Core

4 Synthesis 2-Arylbenzothiazoles via Direct C–H Functionalization

5 Conclusion

Copper-Catalyzed Synthesis, Bio-Evaluation, and in Silico Studies of 2-Aryl-N-alkylbenzimidazoles as Neuroprotective Agents

2-aryl-N-alkylbenzimidazole derivatives synthesized by CuI/PPh3 promoted direct coupling of N-alkylbenzimidazoles with aryl bromides. In vitro neurotoxicities of 20 compounds were evaluated, and the neuroprotective abilities of low-neurotoxic compounds (3b, 3g, 3h, 3i, 3j, 3k, 3o, 3q, 3s and 3t) were investigated against toxicity induced by 1-methyl-4-phenylpyridinium ion (MPP+) in SH-SY5Y neuronal cells. In silico studies revealed that compound 3g could have molecule docking with the following proteins: the bone morphogenetic protein receptor type 1B (BMPR1B), human cytochrome P450 1B1(CYP1B1), Metabotropic glutamate receptor 7 (GRM7), histone deacetylase 6 (HDAC6), 5-hydroxytryptamine receptor 5A (HTR5A), human topoisomerase II beta (TOP2B). A molecular docking simulation of model compound 3g and model protein CYP1B1 has been shown.

Copper-catalyzed Direct 2-Arylation of Benzoxazoles and Benzoimidazoles with Aryl Bromides and Cytotoxicity of Products

An efficient copper-catalyzed direct 2-arylation of benzoxazoles and benzoimidazoles with aryl bromides is presented. The CuI/PPh₃-based catalyst promotes the installation of various aryl and heteroaryl groups through a C-H activation process in good to excellent yields. The cytotoxicity of obtained 2-aryl benzoxazoles (benzoimidazoles) was also evaluated and 1-methyl-2-(naphthalen-1-yl)benzoimidazole showed potential cytotoxicity.

Metal-free phosphonation of benzoxazoles and benzothiazoles under oxidative conditions

A metal-free C-2 phosphonation of benzoxazoles and benzothiazoles with trialkyl phosphites was described.

Copper catalyzed oxidative ortho-C–H benzoxylation of 2-phenylpyridines with benzyl alcohols and benzyl amines as benzoxylation sources

An efficient methodology for the ortho benzoxylation of 2-phenylpyridine via C–H bond activation using benzyl alcohols and benzyl amines as arylcarboxy sources has been developed.