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2022 ◽  
Vol 9 ◽  
Author(s):  
Vipin Singh ◽  
Shanta Raj Lakshmi ◽  
L. Raju Chowhan

A short and efficient multicomponent sequence for synthesizing fused novel polyheterocyclic chromeno spiro-pyrrolidine oxindoles via 1,3-dipolar cycloaddition reaction mediated by reactive azomethine ylides catalyzed by the Graphene Oxide (GO) is reported herein. This approach was utilized for synthesizing fused polyheterocyclic spiro-pyrrolothiazole and spiro-pyrrole oxindoles with yields ranging from good to excellent. A heterogeneous GO catalyst with an ultra-low catalytic loading of 0.05 wt% could proficiently catalyze the reaction without the formation of any side products and can also be visualized by the formation of solid mass in the reaction flask. The methodology is green in nature and the products were isolated by simple filtration without the use of any chromatographic techniques.


2021 ◽  
Vol 947 (1) ◽  
pp. 012028
Author(s):  
Thao Xuan Pham ◽  
Minh Tuan Pham ◽  
Hai Thuong Cao ◽  
Bich Ngoc Nguyen ◽  
Quang Ha Nguyen ◽  
...  

Abstract A high efficient method for the synthesis of 1,3,5-triaryltriazinane derivatives is developed by the condensation reaction of amines and formaldehyde followed by spontaneous cyclotrimerization using CuFe2O4 NPs as an environmentally benign catalyst at room temperature. The copper ferrite was easily separated, reused in good repetitive catalytic performance by simple filtration or external magnet. This process was efficient and compatible with wide range of amines to afford a direct access to nitrogen containing compounds in excellent yields up to 99% and high selectivity.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Badia Imene Cherifi ◽  
Mohammed Belbachir ◽  
Abdelkader Rahmouni

AbstractIn this work, the green polymerization of vinyl acetate is carried out by a new method which consists in the use of clay called Maghnite-Na+ as an ecological catalyst, non-toxic, inexpensive and recyclable by simple filtration. X-ray diffraction (XRD) showed that Maghnite-Na+ is successfully obtained after cationic treatment (sodium) on raw Maghnite. It is an effective alternative to replace toxic catalysts such as benzoyl peroxide (BPO) and Azobisisobutyronitrile (AIBN) which are mostly used during the synthesis of polyvinyl acetate (PVAc) making the polymerization reaction less problematic for the environment. The synthesis reaction is less energetic by the use of recycled polyurethane as container for the reaction mixture and which is considered as a renewable material and a good thermal insulator which maintains the temperature at 0 °C for 6 h. The reaction in bulk is also preferred to avoid the use of a solvent and therefore to stay in the context of green chemistry. In these conditions, the structure of obtained polymer is established by Nuclear Magnetic Resonance Spectroscopy 1H NMR and 13C NMR. Infrared spectroscopy (FT-IR) is also used to confirm the structure of PVAc. Thermogravimetric analysis (TGA) showed that it is thermally stable and it starts to degrade from 330 °C while Differential Scanning calorimetry (DSC) shows that this polymer has a glass transition temperature (Tg  = 50 °C). The composition in PVAc/Maghnite-Na+ (7 wt% of catalyst) is the most tensile resistant with a force of 182 N and a maximum stress of 73.16 MPa, the most flexible (E  = 955 MPa) and the most ductile (εr  = 768%).


Synlett ◽  
2021 ◽  
Author(s):  
Payal Malik ◽  
Isha Jain

AbstractAn indium triflate-catalyzed synthesis of primary carbamates from alcohols and urea as an ecofriendly carbonyl source has been developed. Various linear, branched, and cyclic alcohols were converted into the corresponding carbamates in good to excellent yields. This method also provided access to N-substituted ureas by carbamoylation of amines. All the products were obtained by simple filtration or crystallization, without the need for chromatographic purification. Mechanistic investigations suggest that the carbamoylation reaction proceeds through activation of urea by O-coordination with indium, followed by nucleophilic attack by the alcohol or amine on the carbonyl center of urea. The inexpensive and easily available starting materials and catalyst, the short reaction times, and the ease of product isolation highlight the inherent practicality of the developed method.


2021 ◽  
Vol 15 (1) ◽  
pp. 87-93
Author(s):  
Krisztina Pál ◽  
Andrea Izbékiné Szabolcsik ◽  
Ildikó Bodnár ◽  
Gábor Bellér

Abstract Synthetically produced bathing waters and their effect on seedlings were analysed in our research. The artificially produced bath waters were treated in different ways. Primarily, simple filtration was performed through a layer of silica sand. During the tests, the obtained greywater was investigated before and after the treatment with the help of various water quality parameters. Irrigation was set as the goal of recycling, and germination experiments were performed on mustard seeds. In these experiments, the synthetically generated treated and untreated bath water was used as irrigation water. Considering the results obtained during the germination, it can be said that the treatment is necessary in any case. Based on the results, it was shown that the filtration was not sufficient, so coagulation was used as an additional treatment method, for which we determined the optimal amount of treatment agent as a starting step.


Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1051
Author(s):  
Stefano Serra ◽  
Davide De Simeis ◽  
Stefano Marzorati ◽  
Mattia Valentino

Recently, we described the preparation of the recombinant oleate hydratase from Lactobacillus rhamnosus ATCC 53103. We observed that the purified C-terminal His-tagged enzyme was completely inactive and the catalytic activity was partially restored only in presence of a large amount of flavin adenine dinucleotide (FAD). In the present work, we assess that this hydratase in the presence of the reduced form of flavin adenine dinucleotide (FADH2) is at least one hundred times as active as in the presence of the same concentration of FAD. By means of two different biochemical processes, we demonstrated unambiguously that oleate hydratase from Lactobacillus rhamnosus ATCC 53103 is a FADH2-dependent enzyme. As a first relevant application of this discovery, we devised a preparative procedure for the stereoselective synthesis of (R)-10-hydroxystearic acid. Accordingly, the hydration of oleic acid (up to 50 g/L) is performed on a multigram scale using the recombinant hydratase and FADH2 generated in situ as cofactor. The produced (R)-10-hydroxystearic acid (ee > 97%) precipitates from the reaction solvent (water/glycerol/ethanol) and is conveniently recovered by simple filtration (>90% yield).


2021 ◽  
Author(s):  
Ang Li ◽  
Ce Cui ◽  
Weijie Wang ◽  
Yue Zhang ◽  
Jianyu Zhai ◽  
...  

Abstract Graphene is complexed with cellulose fibers to construct 3D aerogels, which is generally considered to be an environmentally friendly and simple strategy to achieve wide sensing, high sensitivity and low detection of wearable piezoresistive pressure sensors. Here, graphene is incorporated into waste paper fibers with cellulose as the main component to prepare graphene coated waste paper aerogel (GWA) using a simple “filtration-oven drying” method under atmospheric pressure. The GWA was further annealed to obtain the carbonized graphene coated waste paper aerogel (C-GWA) to achieve low density and excellent resilience. The result shows that the C-GWA has a rough outer surface due to the 3D structure formed by interpenetrated fibers and the carbon skeleton with wrinkles. The sensor based on GCA shows low density (25mg/cm3), a wide detection range of 0-132 kPa, an ultra-low detection limit of 2.5 Pa (a green bean, ≈ 53.4 mg), and a high sensitivity of 31.6 kPa− 1. In addition, the sensor based on C-GWA with the excellent performance can be used to detect human motions including the pulse of the human body, cheek blowing and bending of human joints. The result indicates that the sensor based on C-GWA shows great potential for wearable electronic products.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3851
Author(s):  
Qingzheng Wang ◽  
Masafumi Unno ◽  
Hongzhi Liu

In order to enrich hybrid materials, a novel fluorescent silsesquioxane-based polymer (denoted as PCS-OTS) was synthesized by Friedel-Crafts reaction starting from octavinylsilsesquioxane (OVS) with triphenylamine-functionalized silsesquioxane monomer (denoted as OTS) with AlCl3 as catalyst. PCS-OTS possessed a high surface area of 816 m2/g and a unique bimodal pore structure. The triphenylamine unit endowed PCS-OTS with excellent luminescence, which made it act as a sensitive chemical sensor and detect p-nitrophenol with high sensitivity (KSV = 81,230 M−1). Moreover, PCS-OTS can significantly remove dyes, and the respective adsorption capacity for Rhodamine B (RB), Congo red (CR) and Methyl Orange (MO) is 1935, 1420 and 155 mg/g. Additionally, it could simultaneously remove multiple dyes from water by simple filtration and be easily regenerated. This hybrid porous polymer can be a good choice for water treatment.


BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
José Eduardo Cadena-Cruz ◽  
Luis M. Guamán-Ortiz ◽  
Juan Carlos Romero-Benavides ◽  
Natalia Bailon-Moscoso ◽  
Kevin E. Murillo-Sotomayor ◽  
...  

Abstract Background Pyrazoles have attracted particular attention due to the diverse biological activities associated with this heterocyclic system, and some have been shown to be cytotoxic to several human cell lines. Several drugs currently on the market have this heterocycle as the key structural motif, and some have been approved for the treatment of different types of cancer. Results 4,4ʹ-(Arylmethylene)bis(1H-pyrazol-5-ols) derivatives 3a–q were synthetized by a three components reaction of 3-methyl-1-phenyl-5-pyrazolone (1) with various benzaldehydes 2 catalyzed by sodium acetate at room temperature. The structures of all synthesized compounds were characterized by physicochemical properties and spectral means (IR and NMR) and were evaluated for their radical scavenging activity by DPPH assay and tested in vitro on colorectal RKO carcinoma cells in order to determine their cytotoxic properties. All 4,4ʹ-(arylmethylene)bis(1H-pyrazol-5-ols) derivatives 3a–q were synthetized in high to excellent yield, and pure products were isolated by simple filtration. All compounds have good radical scavenging activity, and half of them are more active than ascorbic acid used as standard. Conclusion Several derivatives proved to be cytotoxic in the RKO cell line. In particular, compound 3i proved to be a very potent scavenger with an IC50 of 6.2 ± 0.6 µM and exhibited an IC50 of 9.9 ± 1.1 μM against RKO cell. Autophagy proteins were activated as a survival mechanism, whereas the predominant pathway of death was p53-mediated apoptosis.


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