8055-08-1Relevant articles and documents
Pyridazine N-Oxides as Photoactivatable Surrogates for Reactive Oxygen Species
Basistyi, Vitalii S.,Frederich, James H.
supporting information, p. 1907 - 1912 (2022/03/27)
A method for the photoinduced evolution of atomic oxygen from pyridazine N-oxides was developed. This underexplored oxygen allotrope mediates arene C-H oxidation within complex, polyfunctional molecules. A water-soluble pyridazine N-oxide was also developed and shown to promote photoinduced DNA cleavage in aqueous solution. Taken together, these studies highlight the utility of pyridazine N-oxides as photoactivatable O(3P) precursors for applications in organic synthesis and chemical biology.
Direct Synthesis of Paracetamol via Site-Selective Electrochemical Ritter-type C-H Amination of Phenol
Banerjee, Prabal,Saha, Debarshi,Taily, Irshad Maajid
supporting information, (2022/04/07)
The synthesis of paracetamol still relies on multistep protocols involving the utilization of a stoichiometric amount of oxidizing/reducing or other corrosive agents. Herein we report a regioselective electrochemical Ritter-type reaction at the C(sp2)-H of unprotected phenol toward the environmentally benign and direct synthesis of paracetamol. The reaction proceeds under exogenous oxidant- and catalyst-free conditions. The protocol is scalable, can be deployed to a variety of phenols, and offers a sustainable alternative for the synthesis of paracetamol.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Aluminum Metal-Organic Framework-Ligated Single-Site Nickel(II)-Hydride for Heterogeneous Chemoselective Catalysis
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Dwivedi, Ashutosh,Manna, Kuntal
, p. 3943 - 3957 (2021/04/12)
The development of chemoselective and heterogeneous earth-abundant metal catalysts is essential for environmentally friendly chemical synthesis. We report a highly efficient, chemoselective, and reusable single-site nickel(II) hydride catalyst based on robust and porous aluminum metal-organic frameworks (MOFs) (DUT-5) for hydrogenation of nitro and nitrile compounds to the corresponding amines and hydrogenolysis of aryl ethers under mild conditions. The nickel-hydride catalyst was prepared by the metalation of aluminum hydroxide secondary building units (SBUs) of DUT-5 having the formula of Al(μ2-OH)(bpdc) (bpdc = 4,4′-biphenyldicarboxylate) with NiBr2 followed by a reaction with NaEt3BH. DUT-5-NiH has a broad substrate scope with excellent functional group tolerance in the hydrogenation of aromatic and aliphatic nitro and nitrile compounds under 1 bar H2 and could be recycled and reused at least 10 times. By changing the reaction conditions of the hydrogenation of nitriles, symmetric or unsymmetric secondary amines were also afforded selectively. The experimental and computational studies suggested reversible nitrile coordination to nickel followed by 1,2-insertion of coordinated nitrile into the nickel-hydride bond occurring in the turnover-limiting step. In addition, DUT-5-NiH is also an active catalyst for chemoselective hydrogenolysis of carbon-oxygen bonds in aryl ethers to afford hydrocarbons under atmospheric hydrogen in the absence of any base, which is important for the generation of fuels from biomass. This work highlights the potential of MOF-based single-site earth-abundant metal catalysts for practical and eco-friendly production of chemical feedstocks and biofuels.
Functionalized nanomagnetic graphene by ion liquid containing phosphomolybdic acid for facile and fast synthesis of paracetamol and aspirin
Nasiri, Elahe,Kooshki, Feridoon,Kooti, Mohammad,Rezaeinasab, Rezvan
, (2021/09/02)
A nanocomposite has been synthesized by supporting of polyaniline-modified polyoxometalate-paired poly(ionic liquid) on the surface of magnetic graphene and characterized by various techniques. The fabricated nanocomposite was found to be a versatile catalyst for the synthesis of paracetamol and aspirin drugs showing high activity and selectivity. The observed high catalytic activity of the newly synthesized catalyst, in the preparation of these two important drugs, can be attributed to the presence of graphene, which provides high surface area for the supporting of polyaniline–polyoxometalate pair and also to the strong acidity of the solid acid. This catalytic system has several advantages, such as simple experimental process, easy separation of the product, solvent-free condition, efficient isolation, and recovery of the magnetic catalyst as well as high reusability.
Magnetically recyclable silica-coated ferrite magnetite-K10montmorillonite nanocatalyst and its applications in O, N, and S-acylation reaction under solvent-free conditions
Kumar, Pushpendra,Patil, Shripad M.,Tandon, Nitin,Tandon, Runjhun
, p. 21291 - 21300 (2021/07/01)
Novel silica-coated ferrite nanoparticles supported with montmorillonite (K10) have been prepared successfully by using a simple impregnation method. Further, these nanoparticles were characterized by using different analytical methods like FT-IR, PXRD, EDS, and FE-SEM techniques. In addition, these nanoparticles have been explored for their catalytic activity for the O, N, and S-acylation reactions under solvent-free conditions which gave moderate to excellent yields in a much shorter reaction time. Moreover, these nanoparticles could easily be separated out from the reaction medium after the reaction completion by using an external magnetic field and have been re-used for 10 cycles without any significant loss of the catalytic activity.
Antimalarial Benzimidazole Derivatives Incorporating Phenolic Mannich Base Side Chains Inhibit Microtubule and Hemozoin Formation: Structure-Activity Relationship and in Vivo Oral Efficacy Studies
Dziwornu, Godwin Akpeko,Coertzen, Dina,Leshabane, Meta,Korkor, Constance M.,Cloete, Cleavon K.,Njoroge, Mathew,Gibhard, Liezl,Lawrence, Nina,Reader, Janette,Van Der Watt, Mari?tte,Wittlin, Sergio,Birkholtz, Lyn-Marie,Chibale, Kelly
supporting information, p. 5198 - 5215 (2021/05/06)
A novel series of antimalarial benzimidazole derivatives incorporating phenolic Mannich base side chains at the C2 position, which possess dual asexual blood and sexual stage activities, is presented. Structure-activity relationship studies revealed that the 1-benzylbenzimidazole analogues possessed submicromolar asexual blood and sexual stage activities in contrast to the 1H-benzimidazole analogues, which were only active against asexual blood stage (ABS) parasites. Further, the former demonstrated microtubule inhibitory activity in ABS parasites but more significantly in stage II/III gametocytes. In addition to being bona fide inhibitors of hemozoin formation, the 1H-benzimidazole analogues also showed inhibitory effects on microtubules. In vivo efficacy studies in Plasmodium berghei-infected mice revealed that the frontrunner compound 41 exhibited high efficacy (98% reduction in parasitemia) when dosed orally at 4 × 50 mg/kg. Generally, the compounds were noncytotoxic to mammalian cells.
Nickel-catalyzed deallylation of aryl allyl ethers with hydrosilanes
Ding, Guangni,Fan, Sijie,Wang, Jingyang,Wang, Yu,Wu, Xiaoyu,Xie, Xiaomin,Yang, Liqun,Zhang, Zhaoguo
supporting information, (2021/09/28)
An efficient and mild catalytic deallylation method of aryl allyl ethers is developed, with commercially available Ni(COD)2 as catalyst precursor, simple substituted bipyridine as ligand and air-stable hydrosilanes. The process is compatible with a variety of functional groups and the desired phenol products can be obtained with excellent yields and selectivity. Besides, by detection or isolation of key intermediates, mechanism studies confirm that the deallylation undergoes η3-allylnickel intermediate pathway.
Paracetamol and other acetanilide analogs as inter-molecular hydrogen bonding assisted diamagnetic CEST MRI contrast agents
Chakraborty, Subhayan,Peruncheralathan,Ghosh, Arindam
, p. 6526 - 6534 (2021/02/21)
Paracetamol and a few other acetanilide derivatives are reported as a special class of diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI contrast agents, that exhibit contrast only when the molecules form inter-molecular hydrogen bonding mediated molecular chains or sheets. Without the protection of the hydrogen bonding their contrast producing labile proton exchanges too quickly with the solvent to produce any appreciable contrast. Through a number of variable temperature experiments we demonstrate that under the conditions when the hydrogen bond network breaks and the high exchange returns back, the contrast drops quickly. The well-known analgesic drug paracetamol shows 12% contrast at a concentration of 15 mM at physiological conditions. With the proven safety track-record for human consumption and appreciable physiological contrast, paracetamol shows promise as a diaCEST agent forin vivostudies.
Oxygen bridge bicyclo - [2.2.1] - heptene compounds containing different covalent bullet structures, and preparation and application thereof
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Paragraph 0140, (2021/11/03)
The invention discloses an oxygen bridge bicyclo - [2.2.1] - heptene compound containing different covalent popping structures as well as preparation and application thereof, and belongs to the technical field of targeted drugs. As shown in general formula (I) or general formula (II), furan derivatives and vinylsulfonamide derivatives or vinylsulfonate derivatives containing different covalent popping heads are prepared by reacting Diels-Alder to obtain a compound of the present invention. The compound can be used for preparing anti-breast cancer drugs. A medicament for the degradation of estrogen receptors, a medicament for a mutant estrogen receptor. Compared with the existing anti-breast cancer drug tamoxifen, MCF-7 cells have stronger inhibitory activity and have the ability to down-regulate the estrogen receptor level, and the activity shown for the mutant estrogen receptor is 4 - times of 5-10 hydroxytamoxifen.
