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- Volume 21, Issue 10, 2024
Letters in Organic Chemistry - Volume 21, Issue 10, 2024
Volume 21, Issue 10, 2024
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Recent Advances in Biginelli Reaction using Nanoparticles, Zeolites and Metal Compounds as Catalyst: A Concise Review
Authors: Bhaktiben R. Bhatt, Bharat C. Dixit, Vipul B. Kataria, Ritu B. Dixit and Shaffiq SaiyadThe year 1891 is considered as a historic year in chemical science due to the introduction of novel heterocyclic compounds by P. Biginelli. The classical Biginelli reaction offers 3,4- dihydropyrimidin-2(1H)-ones/thiones in occupancy of acids like Broansted and Lewis. Multifaceted Dihydropyrimidones (DHPMs) have gained much importance due to their high biological activities. Several nanoparticles, zeolites and metal compounds are disclosed to improve the yield of this product. This review subsumes the evolution and effectiveness of catalysts. It summarises the main synthetic routes which are known to obtain DHPMs using these catalysts. The majority of these catalysts delivered satisfying catalytic activity which was more than 80% in the vicinity of producing Biginelli adducts. We hope this review article will be useful to researchers in terms of obtaining higher yields in a shorter time using easily available and reusable catalysts.
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Identification and Synthesis of Oxidative-Degradation and Starting Materials-Attributed Impurities in Lisdexamfetamine Dimesylate
Impurities are an integral part of drug substances, even though they have not been studied in the pharmacological evaluation of the Benefit-Risk (BR) profiles. Hence, understanding their origin and controlling them have prime importance during drug substance development. The structures of some of the impurities in lisdexamfetamine dimesylate, a central nervous system stimulant drug, have been confirmed based on literature and analytical data. The study has been undertaken to evaluate impurities arising from oxidative degradation and impurities due to material attributes. All the listed impurities have been identified, synthesized, and characterized by spectral tools. We have, herein, reported the synthesis of two oxidative degradant impurities, 2-hydroxylisdexamfetamine dimesylate and 4-hydroxylisdexafetamine dimesylate. In addition, chiral isomeric impurities of lisdexamfetamine dimesylate as (S,R), (R,S) and (R,R)-lisdexamfetamine dimesylate have also been reported. These impurities have been identified, synthesized and a control strategy for mitigating risk in lisdexamfetamine dimesylate is provided.
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A Simple and Efficient Path for the Synthesis Antineoplastic Agent (2R,3R,4S,5R)-5-(6-Amino-2-Chloropurin-9-yl)-4-Fluoro-2-(Hydroxymethyl) oxolan-3-ol (Clofarabine)
Authors: Laxmi K. Nagarapu, Chithaluri Sudhakar and Suresh Babu NamanaClofarabine (1) is an anticancer agent used to treat acute leukemia. This work discloses the efforts to develop a convenient, environmentally benign, and high-yielding synthetic protocol leading to Clofarabine (1). The synthesis includes bromination of 2-deoxy-2-β-fluoro-1,3,5-tri-O-benzoyl-1- α-D-ribofuranose (6), followed by C-N coupling with a 2,6-dichloro purine (4) and selective amination consecutively. The proposed total synthesis comprises five steps to afford an overall yield of 65- 70% with 99.85% purity. The present process provides preparation of Clofarabine (1) using a simple purification process with lesser reaction time, better yield, and purity without using toxic and pyrophoric chemicals.
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Preparation and Adsorption Properties of Polymer Particles based on N, N, N', N'-Tetrakis(4-aminophenyl)-1,4-Benzenediamine
Authors: Jian-Yu Huang, Yong Liu, Ting-Hong Huang, Sheng-Zhi Liu and Ai-Ling WuTwo polymer particles have been prepared by the reaction of N, N, N', N'-tetrakis(4- aminophenyl)-1,4-benzenediamine, 4, 4-biphenyldialdehyde and isophthalaldehyde, and characterized by SEM, FTIR and XRD. Based on methylene blue as the model pollutant, the adsorption properties of two polymer particles have been observed by using different adsorbent dosages, adsorption times and adsorption temperatures. Experimental data show that the removal rates of methylene blue wastewater are 74 % for polymer A and 68 % for polymer B, and the removal rates are up to 84% for polymer A and 74 % for polymer B after photo-catalytic treatment. All these suggest that the adsorption performance of polymer A is more excellent than that of polymer B. In addition, the methylene blue adsorption of the two Schiff base products conforms to the Freundlich adsorption isothermal model.
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Antioxidant Activities and Phenolic Composition of Sarcococca saligna Leaves
Sarcococca saligna (D. DON) Muel is a vital plant with several steroidal alkaloids and is effective against syphilis, liver diseases, gastrointestinal tract disease, infections, and inflammation. The present study aimed to investigate the in vitro antioxidant activities and phenolic profile of S. saligna. High-performance liquid chromatography (HPLC) analysis has shown the presence of twelve phenolics namely kaempferol-3-O-glucoside, proanthocyanidin B1, quercetin-3-malonylglucoside- 7-glucoside, kaempferol-3-O-sophorotioside, Isorhamnetin-3-O-glucoside-7-O-rhamnoside, kaempferolhexoside, 4-O-Caffeoyl-5-O-p-coumaroylquinic acid, 3,4-Di-O-caffeoyl-5-O-feruloylquinic acid, 3,4-Di-O-feruloyl-5-O-caffeoylquinic acid, flavogalloyl-HHDP-gluconic acid (lagerstannin B), 3,4-di-O-caffeoylquinic acid and kaempferol-3-(caffeoyldiglucoside)-7-glucoside. The hot water extract showed the highest anti-lipid peroxidative activities. The IC50 value for 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging activity was 71.5 ± 2.1 μg/mL. The extract could chelate the iron and possess reducing activities on phosphomolybenum assay. It is concluded that extracts of S. saligna are rich in antioxidants and contain essential phytochemicals.
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[Bmim][CF3COO] as a Solvent and a Catalyst for the Knoevenagel Condensation
Authors: Nguyen Thi Chung, Vo Cong Dung and Dau Xuan DucA facile and green strategy for the Knoevenagel condensation reaction of aryl aldehydes and active methylene compounds using [Bmim][CF3COO] ionic liquid as a solvent and a catalyst has been introduced. The method features some advantages such as good to excellent yield of products, relatively short reaction time, mild reaction conditions, broad substrate scope, and scalability. Moreover, the ionic liquid solvent could be conveniently recycled and reused up to three times without any considerable loss of catalytic activity. Twelve products were obtained in high yields, and their structures were confirmed by NMR data. A plausible reaction mechanism involving the role of the ionic liquid catalyst was also suggested.
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Polydopamine-Modified Magnetic Nanoparticles (Fe3O4@PDA) for the Copper-Catalyzed Ipso-Hydroxylation of Arylboronic Acids and Subsequent O-Benzylation in Aqueous Media
Authors: Kwang-Beom Lee, Ueon Sang Shin and Seung-Hoi KimA novel advancement has emerged in the realm of catalysis with the development of an innovative method for the Ipso-hydroxylation of arylboronic acids. This approach harnessed the power of bio-compatible polydopamine-coated magnetite support (Fe3O4@PDA) in conjunction with a copper salt, forming a heterogeneous catalytic environment. The resulting catalytic system facilitated oxidative hydroxylation under mild aerobic conditions at room temperature in aqueous conditions. This environmentally friendly process allowed for the seamless conversion of diverse arylboronic acids featuring varying electron-withdrawing or electron-donating groups into the corresponding phenols, achieving remarkably high yields. Notably, the versatility of the catalytic system extended to a one-pot tandem O-benzylation of the resultant phenolic intermediates. The additional dimension of the process underscores its efficiency, offering a streamlined route to synthesizing benzyl phenyl ethers with a commendable level of success. The significance of the present catalytic methodology lies not only in its efficacy but also in its eco-friendly attributes, showcasing the potential for sustainable and efficient transformations in organic synthesis.
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Effective Synthesis of N-Alkyl-3-(Indol-3-yl)Pyrazoles from Ag2CO3- Catalyzed Regioselective Aza-Michael Addition of 5-(Indol-3-yl)-1HPyrazoles
Authors: Xue Zhang, Dashuang Luo, Xuemin Niu, Jian Mo, Haifeng Yu and Xiaobo ZhaoIn this study, the synthesis of N-alkyl-3-(indol-3-yl)pyrazoles was carried out from Ag2CO3 catalyzed regioselective aza-Michael addition of 5-(indol-3-yl)-1H-pyrazoles to α, β-unsaturated carbonyl compounds. In the presence of 10 mol% of Ag2CO3, the reaction smoothly occurred in dichloroethane (DCE) at 120°C to preferentially afford a series of N-alkyl-3-(indol-3-yl)pyrazoles in high yields with good regioselectivity. It was found that 1-methyl-3-(3-methyl-1H-pyrazol-5-yl)-2-phenyl- 1H-indole, 1-benzyl-3-(3-methyl-1H-pyrazol-5-yl)-1H-indole, α, β-unsaturated ketone, and α, β- unsaturated amide exclusively gave 3-(pyrazol-3-yl)indoles in good yields. This reaction features high regioselectivity, mild reaction conditions, good substrate scope and yields, and a commercially available catalyst. Meanwhile, the reaction was also proven to be quite practical by the gram-scale synthesis of N-alkyl-3-(indol-3-yl)pyrazoles in excellent yields with good regioselectivity.
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Volumes & issues
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Volume 21 (2024)
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Volume 20 (2023)
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Volume 19 (2022)
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Volume 18 (2021)
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Volume 17 (2020)
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Volume 16 (2019)
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Volume 15 (2018)
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Volume 14 (2017)
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Volume 13 (2016)
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Volume 12 (2015)
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Volume 11 (2014)
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Volume 10 (2013)
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Volume 9 (2012)
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Volume 8 (2011)
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Volume 7 (2010)
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Volume 6 (2009)
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Volume 5 (2008)
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Volume 4 (2007)
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Volume 3 (2006)
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Volume 2 (2005)
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Volume 1 (2004)