Synthesis and Biological Evaluation of Benzo[b]thiophene Acylhydrazones as Antimicrobial Agents against Multidrug-Resistant Staphylococcus aureus

The benzo[b]thiophene nucleus and the acylhydrazone functional group were combined to prepare three new series of compounds for screening against Staphylococcus aureus. The reaction of substituted benzo[b]thiophene-2-carboxylic hydrazide and various aromatic or heteroaromatic aldehydes led to a collection of 26 final products with extensive structural diversification on the aromatic ring and on position 6 of the benzo[b]thiophene nucleus. The screening lead to the identification of eight hits, including (E)-6-chloro-N’-(pyridin-2-ylmethylene)benzo[b]thiophene-2-carbohydrazide (II.b), a non-cytotoxic derivative showing a minimal inhibitory concentration of 4 µg/mL on three S. aureus strains, among which were a reference classical strain and two clinically isolated strains resistant to methicillin and daptomycin, respectively.

Deconstructive Cycloaromatization Strategy towards N,O-Bidentate Ligands and Their Four-Coordinate Organoboron Complexes

The innovative construction of novel N,O-bidentate ligands and N,O π-conjugated four-coordinate organoboron complexes represent a long-standing challenge for chemists. Here, we report an unprecedented and straightforward approach for the construction of N,O-bidentate ligands and their organoboron complexes via the merge of ring deconstruction with cycloaromatization of indolizines and cyclopropenones. Without any catalysts, our method is able to deliver a series of polyaryl 2-(pyridin-2-yl)phenol ligands, N,O π-conjugated organoboron (BF2 and BAr2) complexes with good functional-group compatibility which are difficult or even impossible to synthesize with previous methods. Importantly, the formed N,O-bidentate ligands were easy to scale up and derive with valuable drugs and active molecules. In addition, the photoluminescence measurements and the HOMO/LUMO gap have been investigated, the results have revealed that N,O π-conjugated tetracoordinate boron complexes display bright fluorescence, large Stokes shifts, and good quantum yields (Φlum = 0.15–0.45). The method proposed by the paper will inspire the development of various N,O-bidentate metal and boron complexes, which is expected to move the area of catalysis chemistry and material science forward.

General Electrochemical Minisci Alkylation of N-Heteroarenes with Alkyl Halides

Herein, we report, for the first time, a general, facile and environmentally friendly Minisci-type alkylation of N-heteroarenes under simple and straightforward electrochemical conditions using widely available alkyl halides as radical precursors. Primary, secondary and tertiary alkyl radicals have shown to be efficiently generated and coupled with a large variety of N-heteroarenes. The method presents a very high functional group tolerance, including various heterocyclic-based natural products, which highlights the robustness of the methodology. This applicability has been further proved in the synthesis of various interesting biologically valuable building blocks. In addition, we have proposed a mechanism based on different proofs and electrochemical evidences.

Evidences of Microplastic in Air and Street Dust: A Case Study of Varanasi City, India

Microplastics (MPs) are ubiquitous in our environment. Its presence in air, water and soil makes it a serious threat to living organisms. The present study aimed to assess the availability of MPs in air and street dust of a metropolitan city Varanasi, India. Suspended dust samples and street dust samples were collected from various sampling sites. The assessment of MPs was conducted by for physical identification binocular microscopy, fluorescence microscopy and Scanning Electron Microscopy (SEM), while elemental analysis done by Energy Dispersive X-Ray Analysis (EDX). and finally, Fourier-transform infrared spectroscopy (FTIR) was used for functional group analysis. the presence of MPs in both suspended dust and street dust samples of all selected sampling sites was confirmed by results. MPs of different color with the shape of Fragments, Films, Spherules and Fibers were observed in the study. However, most of the MPs were less than 1mm in size. The MPs identified in our study were majorly polypropylene, polystyrene, polyethylene, polyethylene terephthalate, polyester, and polyvinyl chloride. EDX analysis showed presence of trace elements like aluminum, cadmium, magnesium, sodium, and silicon apart from carbon and oxygen, which indicates the presence of additives or adsorption capacity of MPs. Confirmation of MPs in the air of a locality of Varanasi explains the need of deep research in this concerned field to protect our future from negative impacts of breathing MPs.

Influence of Functional Group Modification on the Toxicity of Nanoplastics

Nanoplastics (NPs) are ubiquitous in harvested organisms at various trophic levels, and more concerns on their diverse responses and wide species-dependent sensitivity are continuously increasing. However, systematic study on the toxic effects of NPs with different functional group modifications is still limited. In this review, we gathered and analyzed the toxic effects of NPs with different functional groups on microorganisms, plants, animals, and mammalian/human cells in vitro. The corresponding toxic mechanisms were also described. In general, most up-to-date relevant studies focus on amino (−NH2) or carboxyl (−COOH)-modified polystyrene (PS) NPs, while research on other materials and functional groups is lacking. Positively charged PS-NH2 NPs induced stronger toxicity than negatively charged PS-COOH. Plausible toxicity mechanisms mainly include membrane interaction and disruption, reactive oxygen species generation, and protein corona and eco-corona formations, and they were influenced by surface charges of NPs. The effects of NPs in the long-term exposure and in the real environment world also warrant further study.

Class Map: Improving Students’ Skills of Organic Synthesis in Learning Organic Chemistry for Pre-University Students

This action research uses the Kemmis & Mc Taggart Model (1988) to improve the skills for science stream of pre-university students in organic synthesis topic to convert one functional group to another by using Class Map in learning Organic Chemistry. The objectives of this study were to improve memory skills in conversion of functional groups in an Organic Chemistry reaction and to cultivate students' interest in the subject of Organic Chemistry. A total of six students of 6 Delta 2, SMK Sultan Abu Bakar were involved in this study. Preliminary surveys were conducted through observations, document analysis and interviews. The results of the survey showed that students could not remember the conversion of functional group well because in the Semester Three chemistry syllabus, there are too many chemical reactions, causing students less interested in learning Organic Chemistry. Students were exposed to the Class Map within two months. The test results displayed that (i) students can recall the functional group conversion reaction in an Organic Chemistry and (ii) students can apply the organic reactions learned in answering questions. The findings of the interviews showed that students can cultivate an interest in Organic Chemistry subject.

Chemoselective N-acylation of indoles using thioesters as acyl source

The selective acylation of indoles often requires sensitive and reactive acyl chloride derivatives. Here, we report a mild, efficient, functional group tolerant, and highly chemoselective N-acylation of indoles using thioesters as a stable acyl source. A series of indoleamides have been obtained with moderate to good yields. In addition, heterocycles, such as carbazole, can also be used as nucleophiles in this reaction.