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Oxide Nanoparticles in Heterogeneous Catalysis
Published in Varun Rawat, Anirban Das, Chandra Mohan Srivastava, Heterogeneous Catalysis in Organic Transformations, 2022
Garima Sachdeva, Jyoti Dhariwal, Monika Vats, Varun Rawat, Manish Srivastava, Anamika Srivastava
The isoquinoline nucleus consists of an aromatic ring fused with pyridine and is isolated along with other biologically important plant alkaloids. Krishnakumar and co-workers represented an effective ZnO nanoparticle-mediated reaction for the synthesis of bis-isoquinolines. Synthesis of bis-isoquinolines involved two steps – firstly, homophthalic acid reacted with acid chloride to give isocoumarins, which on further condensation with 1,7-heptadiamine afforded bis-isoquinoline in good yields (Figure 2.15) [34]. It was seen that rate of reaction increases in the presence of EDG as compared with EWG. The methodology utilizes mild reaction conditions, which makes it proficient in comparison to other techniques.
Plant responses to per- and polyfluoroalkyl substances (PFAS): a molecular perspective
Published in International Journal of Phytoremediation, 2023
Ayesha Karamat, Rouzbeh Tehrani, Gregory D. Foster, Benoit Van Aken
Liu et al. (2022) analyzed gene expression in the alga C. pyrenoidosa exposed to PFBS and FBSA, which revealed downregulation of SOD (SOD2) and peroxidase genes (PRDX5), and upregulation of glutathione peroxidase genes (GPX). The authors then proposed that these changes would increase H2O2 and decrease free glutathione in exposed tissues, explaining the phytotoxic effect of PFAS. The downregulation of SOD2 was consistent with a decrease of the SOD activity in exposed plants. However, results at the transcriptomic level were not always in agreement with the recorded enzymatic activities. In their experiment with E. crassipes exposed to PFOS, Li et al. (2020c) observed downregulation of a SOD gene (Mn-SOD) in plants exposed to high level of PFOS (10 mg L−1), while no significant change in SOD activity was measured. In another transcriptomic analysis, exposure of soil-grown soybean (Glycine max) plants to the short-chain PFBA did not result in significant changes in the level of expression of SOD and CAT, although the activities of these enzymes decreased in plants exposed to even low concentration (100 ng/L), suggesting posttranslational inhibition of the enzymes by PFBA (Omagamre et al. 2022). In this study, enrichment of pathways involved in alkaloid biosynthesis (e.g., isoquinoline, tropane piperidine, and pyridine) led the authors to suggest a non-enzymatic response to ROS.
Peony seed oil microemulsion that enhances the antioxidant, antitumor, and antibacterial activities of berberine hydrochloride
Published in Journal of Dispersion Science and Technology, 2022
Meng Zhang, Jinpeng Liu, Zhenhua Feng, Zhongni Wang, Tao An, Feng Liu
Berberine hydrochloride (BH) extracted from plants is an isoquinoline alkaloid and is in the form of a yellow, crystalline needlelike powder.[1,2] It has shown bacteriostatic, antitumor, and anti-inflammatory effects, and is widely used to treat gastrointestinal diseases such as diarrhea.[3–5] However, the low gastrointestinal absorbability of BH has restricted its application in the food industry and pharmaceuticals. To improve the gastrointestinal absorbability antioxidant, or other activities of BH, researchers have loaded BH in emulsion, hydrogel and liposome.[6,7] Studies have found that the BH/β-cyclodextrin inclusion complex - loaded bacterial cellulose hydrogels could realize the sustained release of BH in simulated gastrointestinal fluid at different pH conditions, which can improve the action time and bioavailability of BH.[8]
Odorless, convenient and one-pot synthesis of thioethers from organic halides and thiourea
Published in Journal of Sulfur Chemistry, 2019
Aazam Monfared, Sheida Ahmadi, Zahra Rahmani, Parvaneh Delir Kheirollahi Nezhad, Akram Hosseinian
Synthesis of thioether derivatives via catalyst-free and base-free C–S cross-coupling reaction between organic halides and thiourea has been scarcely studied; in fact, only one example of such a reaction was reported thus far. In this report, Khan and co-workers showed that treatment of N-heteroaryl chlorides 64 with 0.5 equiv. of thiourea in refluxing ethanol, resulted in symmetrical thioethers 65 in high to excellent yields (Scheme 26) [69]. The methodology was applicable to various N-heteroaryl chlorides including isoquinoline, pyridine, pyrazine, pyrimidine, 1,3,5-triazine, imidazole, thiazole chlorides. It should be mentioned that the amount of thiourea plays an important role in this reaction. Interestingly, when the reaction was carried out in the presence of 0.95 equiv. of thiourea, the corresponding thiols were obtained in high yields without thioether product formation.