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Micronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Unlike coenzymes, true cofactors are inorganic compounds. Usually, cofactors are metal ions. Thousands of enzymatic reactions require metal ion cofactors in functions ranging from Lewis acid catalysis to redox catalysis and electron transfer (91).
Chalcone (1,3-Diphenyl-2-Propene-1-One) Scaffold Bearing Natural Compounds as Nitric Oxide Inhibitors: Promising Antiedema Agents
Published in Debarshi Kar Mahapatra, Cristóbal Noé Aguilar, A. K. Haghi, Applied Pharmaceutical Practice and Nutraceuticals, 2021
Debarshi Kar Mahapatra, Sanjay Kumar Bharti, Vivek Asati
Chemical reactions play a major role in the journey of chalcones.27 It interchanges into flavonoids in the presence of acid and the reversal into flavanone occurs by base.28 This scaffold serves as a template structure for the elucidation of flavanones, tannins, flavonoids, and chromanochro-manes.29 Nonpharmacological utilization such as insecticides, scintillator, sweeteners in confectionaries, polymerization agents in product development, chemosensor for detection, catalyst in specific reactions, chromophores in dying industries, fluorescent polymeric agents, fluorescent whitening agent, etc. have been reported.30 Numerous traditional high-yield methods such as Suzuki–Miyaura reaction, Claisen–Schmidt reaction, Julia–Kocienski reaction, Friedel–Crafts reaction, Sonogashira isomerization coupling, one-pot reactions, direct crossed-coupling reaction, microwave-assisted reactions, solvent-free reactions, carbonylative Heck coupling reaction, solid acid catalyst mediated reactions, etc. have been into applications in industrial-scale and academic-scale.31,32
Fundamentals of Modern Peptide Synthesis
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Achiral amino acids derived from glycine or racemic mixtures of D, L-methionine, or D, L-alanine have been produced by chemical synthesis. In 1850 the first chemical syntheses were reported. The name of this synthesis is the Strecker synthesis. In this method the reaction was assisted by acid catalysts, metal cyanide, and the reaction was to convert an aldehyde or ketone and amine or ammonia to α-amino acids (Strecker 1850).
Potential anti-neuroinflammatory NF-кB inhibitors based on 3,4-dihydronaphthalen-1(2H)-one derivatives
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Yue Sun, Yan-Qiu Zhou, Yin-Kai Liu, Hong-Qin Zhang, Gui-Ge Hou, Qing-Guo Meng, Yun Hou
In this study, the synthetic routes to 3,4-dihydronaphthalen-1(2H)-one derivatives are shown in Schemes 1 and 2. A key intermediate, 7-methoxy-3,4-dihydronaphthalen-1(2H)-one (5), was prepared with an overall yield of 48% using the three steps based on the method described in the literature21,24. First, anisole (1) and succinic anhydride (2) were combined to generate 4–(4-methoxyphenyl)-4-oxobutanoic acid (3) by Lewis acid catalysis (anhydrous AlCl3) with a 92% yield. Secondly, after Wolff-Kishner-Huang-Minlon reduction of 3, 4-phenoxybutanoic acid 4 was generated with an 86% yield. Then, the key intermediate 5 was prepared for cyclisation in the presence of PPA with a lower yield of 65%. Lastly, 5 and several aromatic aldehydes were subjected to Claisen-Schmidt condensation to yield a series of new 3,4-dihydronaphthalen-1(2H)-one derivatives (6a-n). The yields of 6a-n reached approximately 80–91%. During this last step, dry HCl, aqueous NaOH, or other bases can be chosen as the catalyst27. Considering its environmental friendliness and availability to laboratories, a 20% NaOH solution was selected as the catalyst (Scheme 1).
Interaction pattern and in vitro, in vivo release behavior of simvastatin-loaded chitosan nanoformulation
Published in Drug Development and Industrial Pharmacy, 2019
Irisappan Sarathchandiran, Kailasam Koumaravelou, Nandakumar Selvasudha
The formed bond should dissociate in biological fluids to release drug to produce its required pharmacological actions. The physical and chemical properties of the hydrophilic matrices, in terms of their interactions with the environment and the drugs, are pivotal for release performance. The release of the drug from a pharmaceutical form is mediated by the ability of the matrix to hydrate, swell, and erode, as well as by diffusion of the drug through the hydrophilic gel network thus formed. Thus, the specific interactions between the drug and the excipients including the hydrophilic polymers that may constitute the matrix are important in the diffusion of the drug through the hydrated network. It was reported in this context that chitosan–simvastatin interaction plays a significant role on the drug release behavior of this nanoparticulate DDS. In general for acidic materials, faster hydrolysis of ester bond is expected, due to acid catalysis. For basic materials, two effects can be observed: base catalysis of the ester bond cleavage and neutralization of carboxy end groups of polymer chains which restricts the autocatalytic effect of acidic chain ends. Thus, degradation can be accelerated or retarded by a base, depending on the relative contribution of the above two effects [8]. Therefore, it is necessary to find out whether the drug of choice-simvastatin will interact beneficially with the chitosan or not. The extent of this interaction is also very much helpful in order to find out the suitability of the polymer for further in vivo study.
Recent progress of functionalised graphene oxide in cancer therapy
Published in Journal of Drug Targeting, 2019
Lingyun Yi, Yanan Zhang, Xiaoqun Shi, Xiyou Du, Xinyi Wang, Aihua Yu, Guangxi Zhai
The covalent modification, GO combines with some groups through chemical reaction, is one of the most extensive methods to functionalise GO [41]. It may destroy the original structure of GO, but it endows the GO derivatives with more stability in the physiological solution [42]. Among these, acylation is the most common approach to promoting covalent attachment of molecular precursors to the GO surface. Stankovich et al. [43] first modified GO via a covalent method in 2006. They used isocyanates to react with the hydroxyl and carboxyl groups of GO, obtaining functionalised GO nanoplatelets which had good dispersion in polar aprotic solvents. In addition, the sulphonated GO as a highly efficient solid acid catalyst has attracted attention of many researchers [44]. Most of covalent modification strategies utilised those surface groups on GO such as hydroxyl, carboxyl groups and epoxy groups, while some reactions between GO and polymers needed a linker such as active double bond. For example, Li et al. [45] and Wen et al. [46] conjugated PEG to GO via a cleavable disulphide bond (GO-SS-PEG), which exhibited great biocompatibility, considerable degradability and the targeting ability of delivering drugs to specific tumour cells with high intracellular glutathione (GSH) concentrations via redox reaction.