Pyrazole containing natural products: Synthetic preview and biological significance

Conductive polymers in water treatment: A review

Adsorption as a technique is preferred to these other methods in the mitigation of methyl orange (MO) because of its simplicity in design and operation, indifferent sensitivity towards toxicants and low operational cost. This study is aimed at evaluating the performance of various adsorbent groups in the mitigation of MO from aqueous solutions. It will help reduce the arbitrary choice of adsorbent types for MO adsorption leading to a reduction in the amount of published literature with little/incremental contributions to the field. The study was based on an analysis of over 240 published works of literature on the subject within the last 5 years. The adsorbents were classified into the following seven groups based on their chemical composition; biosorbents, activated carbon, biochar, clays and minerals, polymers and resins, nanoparticles, and composites. In terms of frequency of utilisation of adsorbent group, composites were the most frequently used (>40%). It was observed that nanoparticles and polymers were the most frequently used constituents in the manufacture of composite adsorbents for MO. The choice of nanoparticles in composite adsorbents could be due to their flexibility in going into the matrices of other material types due to their small sizes. Polymers also act as good matrices for immobilising other composite constituents. Nanoparticles was the best adsorbent group for MO uptake. Clays and minerals had the greatest proportion of adsorbents with MO uptake capacity greater than the 1000 ​mg/g threshold.

Adsorption of methyl orange: A review on adsorbent performance

Significance of conducting polyaniline based composites for the removal of dyes and heavy metals from aqueous solution and wastewaters - A review

A review on polyaniline composites: Synthesis, characterization, and applications

Chitosan–polyaniline–copper(II) oxide (Ch–PANI–CuO) nanocomposite has been synthesized using batch adsorption method. It was characterized using UV–Vis, scanning electron microscopy (SEM), X-ray diffraction and Fourier transform infrared (FTIR) and transmission electron microscopy (TEM). The SEM and TEM showed that the surface of the nanocomposite was rough and porous with pleats, which is probably responsible for better dye adsorption. The maximum percentage of dye degradation was found to be 94.6% for methyl orange dye. The desorption study and FTIR results confirmed the presence of hydroxyl and amino functional groups. The results clearly indicate that the polymer matrix could be used as an adsorbent for the removal of methyl orange from aqueous solution.

Chitosan–polyaniline–copper(II) oxide hybrid composite for the removal of methyl orange dye

The title compounds (IV) (14 examples) are obtained by microwave assisted cyclocondensation of substituted chalcones (III) with hydrazide of benzotriazole (II).

MW Assisted Synthesis of Some Pyrazoles Containing Benzotriazole Moiety: An Environmentally Benign Approach.

By definition, Green chemistry includes those chemical syntheses, which are environmentally benign. Microwave assisted organic synthesis (MAOS) creates none or minimum by-products which pollute the atmosphere. Therefore it has been regarded as an environmentally benign approach for synthesizing organic compounds. Microwave irradiation has been widely exploited in the last few decades to carry out a striking number of organic syntheses 1-4 , benefited from the dielectric heating in terms of reduced reaction times and increased yields 5 . Chalcones or benzylideneacetophenones are important constituents of natural sources. They were first isolated from Chinese liquorice (Glycyrrhizae inflata). It has 1,3-diaryl-1ones skeletal system, which was recognized as the main pharmacophore for chalcones. Stable chalcone moieties cannot be isolated from plants because of the presence of an enzyme (chalcone synthetase) which converts chalcones immediately into flavanones. The pyrazole ring is a prominent structural motif found in numerous pharmaceutically active compounds. This is mainly due to the ease of preparation and the important biological activity exhibited by this nucleus. Since pyrazole framework plays an essential role in biologically active compounds, it therefore represents an interesting template for combinatorial as well as medicinal chemistry 6-10 . The pyrazole nucleus is an ubiquitous feature of pharmacological interest and has been proven to be a fertile source of medicinal agents such as antibacterial 11 , antifungal 12 , antiviral 13 , antitubercular 14 , antiamoebic 15 , antiandrogenic 16 , etc. Some of these compounds have also exhibited antiinflammatory 17 , antidiabetic 18 , anaesthetic 19 , analgesic 20 and antiparasitic 21 properties. Looking at such a wide scope available for pyrazoles as target molecules in medicinal chemistry, some novel pyrazole derivatives containing benztriazole moieties have been synthesized, characterized and screened for their antimicrobial activity.

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Note MW assisted synthesis of some pyrazoles containing benzotriazole moiety: An environmentally benign approach

Hydrogen peroxide readily oxidized phenols to corresponding quinones in the presence of Fe(III) as a catalyst, both are supported on alumina. The reaction was carried out under microwave irradiation. The effects of Fe (III) catalyst and microwave irradiation reduces the time of reaction and the yield of product was also improved.

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MICROWAVE ASSISTED Fe(III) CATALYSED OXIDATION OF PHENOL BY HYDROGEN PEROXIDE SUPPORTED ON ALUMINA

The reaction sequence involves microwave induced preparation of N-(2-oxo-1, 2-dihydro-3’Hindol-3-ylidene) pyridine-4-carbohydrazide (3) from isoniazid (1) and isatin (2) followed by the cyclocondensation of (3) and mercaptoacetic acid under microwave conditions to achieve the synthesis of spiro-[indole-thiazolidine] compound (4). The resulting compound was then allowed to react with various aromatic aldehydes to afford arylidene derivatives (5a-d).

Manish Kumar Rawal

Papers

Chitosan–polyaniline–copper(II) oxide hybrid composite for the removal of methyl orange dye

MW Assisted Synthesis of Some Pyrazoles Containing Benzotriazole Moiety: An Environmentally Benign Approach.

Note MW assisted synthesis of some pyrazoles containing benzotriazole moiety: An environmentally benign approach

MICROWAVE ASSISTED Fe(III) CATALYSED OXIDATION OF PHENOL BY HYDROGEN PEROXIDE SUPPORTED ON ALUMINA

Microwave Assisted Synthesis of Some New Spiro-[indole-thiazolidine] Derivatives : A Green Chemical Pathway