108,507 results match your criteria hydrogen bonds

Enhanced adsorption of resorcinol onto phosphate functionalized graphene oxide synthesized via Arbuzov Reaction: A proposed mechanism of hydrogen bonding and π-π interactions.

Chemosphere 2021 Apr 30;280:130730. Epub 2021 Apr 30.

Department of Chemistry, University of Louisiana at Lafayette, P. O. Box 43700, Lafayette, LA, 70504, USA.

Phosphate functionalized graphene oxide (PGO) was successfully prepared by Arbuzov reaction and employed for adsorption of resorcinol from an aqueous phase. The phosphate functional groups were successfully incorporated onto the PGO surface by the formation of P-C bonds as identified by the analysis of FTIR and XPS spectra. The evaluation of adsorption capacity of resorcinol onto PGO exhibited significant improvement of resorcinol removal, achieving an adsorption capacity of 50. Read More

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Human transthyretin binding affinity of halogenated thiophenols and halogenated phenols: An in vitro and in silico study.

Chemosphere 2021 Apr 30;280:130627. Epub 2021 Apr 30.

Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China. Electronic address:

Serious harmful effects have been reported for thiophenols, which are widely used industrial materials. To date, little information is available on whether such chemicals can elicit endocrine-related detrimental effects. Herein the potential binding affinity and underlying mechanism of action between human transthyretin (hTTR) and seven halogenated-thiophenols were examined experimentally and computationally. Read More

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Non-thermal plasma-induced DMPO-OH yields hydrogen peroxide.

Arch Biochem Biophys 2021 May 5:108901. Epub 2021 May 5.

Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Showa-Ku, Nagoya, 466-8550, Japan; Center for Low-temperature Plasma Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8603, Japan. Electronic address:

Recent developments in electronics have enabled the medical applications of non-thermal plasma (NTP), which elicits reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as hydroxyl radical (OH), hydrogen peroxide (HO), singlet oxygen (O), superoxide (O), ozone, and nitric oxide at near-physiological temperatures. In preclinical studies or human clinical trials, NTP promotes blood coagulation, eradication of bacterial, viral and biofilm-related infections, wound healing, and cancer cell death. To elucidate the solution-phase biological effects of NTP in the presence of biocompatible reducing agents, we employed electron paramagnetic resonance (EPR) spectroscopy to quantify OH using a spin-trapping probe, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO); O using a fluorescent probe; and O and HO using luminescent probes in the presence of thiols or tempol. Read More

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A synthetic galectin mimic.

Angew Chem Int Ed Engl 2021 May 8. Epub 2021 May 8.

University of Amsterdam Faculty of Science: Universiteit van Amsterdam Faculteit der Natuurwetenschappen Wiskunde en Informatica, van 't Hoff Institute for Molecular Sciences, NETHERLANDS.

Galectins are a galactoside specific subclass of carbohydrate binding proteins (lectins) involved in various cellular activities, certain cancers, infections, inflammations and many other biological processes. The molecular basis for the selectivity of galectins is well-documented and revolves around appropriate interaction complementarity: an aromatic residue for C-H···π interactions and polar residues for (charge assisted) hydrogen bonds with the axial hydroxyl group of a galactoside. Despite this knowledge, no synthetic mimics are currently available. Read More

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A modified method to calculate dual-isotope slopes for the natural attenuation of organic pollutants in the environment.

Environ Sci Pollut Res Int 2021 May 8. Epub 2021 May 8.

School of Urban Planning and Design, Shenzhen Graduate School, Peking University, Shenzhen, 518055, People's Republic of China.

Two-dimensional compound-specific isotope analysis has become a powerful tool for distinguishing reaction mechanisms. Lambda (Λ), an essential and important parameter for processing two-dimensional isotope fractionation data, exhibits values specific to a reaction mechanism. In the present article, we modified the existing algorithms for calculation of lambdas based on a review of current methods. Read More

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Study of ground state interactions of enantiopure chiral quaternary ammonium salts and amides, nitroalkanes, nitroalkenes, esters, heterocycles, ketones and fluoroamides.

Chemistry 2021 May 8. Epub 2021 May 8.

Johannes Kepler Universität Linz: Johannes Kepler Universitat Linz, of Chemistry, AUSTRIA.

Chiral Phase-Transfer Catalysis provides high level of enantiocontrol, however no experimental data showed the interaction of catalysts and substrates. We have carried out 1H-NMR titration of Cinchona and Maruoka ammonium bromides vs nitro, carbonyl, heterocycles, and N-F containing compounds. We found that neutral organic species and quaternary ammonium salts interacted via an ensemble of catalyst +N-C-H and (sp2)C-H, specific for each substrate studied. Read More

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Unraveling the mechanism of efficient adsorption of riboflavin onto activated biochar derived from algal blooms.

J Environ Manage 2021 May 5;291:112725. Epub 2021 May 5.

School of Geographic Sciences, Nantong University, Nantong, 226007, China. Electronic address:

Riboflavin is commercially produced primarily by bio-fermentation. Nonetheless, purification and separation are particularly complex and costly. Adsorption from the fermentation liquor is an alternative riboflavin separation technology during which a cost-efficient adsorbent is highly desired. Read More

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The potential endocrine disruption mechanism of anthelmintic drug niclosamide by activating estrogen receptors and estrogen-related receptors.

Toxicology 2021 May 4:152805. Epub 2021 May 4.

College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, PR China. Electronic address:

Niclosamide (NIC), a helminthic drug used widely for controlling schistosomiasis, can reportedly disrupt the endocrine system. However, its underlying mechanisms are still unclear. In this study, we revealed the potential endocrine disruption mechanism of NIC by activating estrogen receptors (ERs) and estrogen-related receptors (ERRs). Read More

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Visualization of Acoustic Energy Absorption in Confined Aqueous Solutions by PNIPAM Microgels: Effects of Bulk Viscosity.

Langmuir 2021 May 7. Epub 2021 May 7.

Department of Physics, Technische Universität Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.

Ultrasound propagation in liquids is highly influenced by its attenuation due to viscous damping. The dissipated energy will be partially absorbed by the liquid due to its dynamic viscosity as well as its bulk viscosity. The former results in the generation of a flow that is called acoustic streaming, and the latter is associated with the vibrational and rotational relaxation of liquid molecules. Read More

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Role of Water Molecules and Helix Structure Stabilization in the Laser-Induced Disruption of Amyloid Fibrils Observed by Nonequilibrium Molecular Dynamics Simulations.

J Phys Chem B 2021 May 7. Epub 2021 May 7.

IR Free Electron Laser Research Center, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Noda, Chiba 278-8510, Japan.

Water plays a crucial role in the formation and destruction of biomolecular structures. The mechanism for destroying biomolecular structures was thought to be an active breaking of hydrogen bonds by water molecules. However, using nonequilibrium molecular dynamics simulations, in which an amyloid-β amyloid fibril was destroyed via infrared free-electron laser (IR-FEL) irradiation, we discovered a new mechanism, in which water molecules disrupt protein aggregates. Read More

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Zirconium Metal-Organic Frameworks Integrating Chloride Ions for Ammonia Capture and/or Chemical Separation.

ACS Appl Mater Interfaces 2021 May 7. Epub 2021 May 7.

Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.

Ammonia capture by porous materials is relevant to protection of humans from chemical threats, while ammonia separation may be relevant to its isolation and use following generation by emerging electrochemical schemes. Our previous work described both reversible and irreversible interactions of ammonia with the metal-organic framework (MOF) material, NU-1000, following thermal treatment at either 120 or 300 °C. In the present work, we have examined NU-1000-Cl, a variant that features a modified node structure-at ambient temperature, Zr(μ-O)(μ-OH)(HO) in place of Zr(μ-O)(μ-OH)(OH)(HO). Read More

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Phytoglycogen Nanoparticles: Nature-Derived Superlubricants.

ACS Nano 2021 May 7. Epub 2021 May 7.

Department of Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3H6.

Phytoglycogen nanoparticles (PhG NPs), a single-molecule highly branched polysaccharide, exhibit excellent water retention, due to the abundance of close-packed hydroxyl groups forming hydrogen bonds with water. Here we report lubrication properties of close-packed adsorbed monolayers of PhG NPs acting as boundary lubricants. Using direct surface force measurements, we show that the hydrated nature of the NP layer results in its striking lubrication performance, with two distinct confinement-controlled friction coefficients. Read More

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Photocuring Three-Dimensional Printing of Thermoplastic Polymers Enabled by Hydrogen Bonds.

ACS Appl Mater Interfaces 2021 May 7. Epub 2021 May 7.

College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, P. R. China.

The advent of 3D printing has led to a new era of highly customized products. Printing reprocessable thermoplastic polymers is limited to slow printing techniques such as fused deposition modeling. Photocuring 3D printing is a high-speed 3D printing technique suitable for photocurable thermosetting resins because the cross-linked 3D network could achieve rapid solid-liquid separation during printing. Read More

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Insights into the substrate discrimination mechanisms of methyl-CpG-binding domain 4.

Biochem J 2021 May 7. Epub 2021 May 7.

The University of Texas at Austin, Austin, Texas, United States.

G:T mismatches, the major mispairs generated during DNA metabolism, are repaired in part by mismatch-specific DNA glycosylases such as methyl-CpG-binding domain 4 (MBD4) and thymine DNA glycosylase (TDG). Mismatch-specific DNA glycosylases must discriminate the mismatches against million-fold excess correct base pairs. MBD4 efficiently removes thymine opposite guanine but not opposite adenine. Read More

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Molecular Dynamics Studies of Therapeutic Liquid Mixtures and Their Binding to Mycobacteria.

Front Pharmacol 2021 20;12:626735. Epub 2021 Apr 20.

Red Glead Discovery AB, Lund, Sweden.

Tuberculosis is an highly contagious disease still considered by the WHO as one of most infectious diseases worldwide. The therapeutic approach, used to prevent and treat tuberculosis targets the complex, comprises a combination of drugs administrated for long periods of time, which, in many cases, could cause several adverse effects and, consequently, low compliance of the patient to the treatment and drug-resistance. Therefore, therapeutic liquid mixtures formulated with anti-tuberculosis drugs and/or adjuvants in tuberculosis therapy are an interesting approach to prevent toxic effects and resistance to anti-tuberculosis drugs. Read More

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Triangular Interchalcogen Interactions: A Joint Crystallographic Data Analysis and Theoretical Study.

J Phys Chem A 2021 May 6. Epub 2021 May 6.

Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China.

Noncovalent chalcogen-chalcogen interactions are being actively investigated from both crystallographic and theoretical viewpoints in recent years. According to our search of the Cambridge Structural Database (CSD), a huge number of crystal structures containing triangular Ch synthons were extracted. On the basis of the results of the CSD survey, a series of trimeric complexes of organic divalent chalcogen molecules were selected to model such interaction motifs. Read More

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Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Apr 21;258:119859. Epub 2021 Apr 21.

School of Medical Engineering, Xinxiang Medical University, Xinxiang, Henan 453003, PR China. Electronic address:

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Read More

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Benzoic acid-modified monolithic column for separation of hydrophilic compounds by capillary electrochromatography with high content of water in mobile phase.

J Chromatogr A 2021 Apr 22;1647:462166. Epub 2021 Apr 22.

Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 100080, China. Electronic address:

Hydrophilic column combined with mobile phase containing high content of water is a green method for the separation of polar compounds, but there are few related studies, and the separation efficiency and performance of existing columns still needs to be improved. In this work, a novel monolithic column for separation of hydrophilic compounds under both high water content and HILIC condition, was prepared by in-situ polymerization using 4-vinylbenzoic acid (VBA) and 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol (AMAP) as functional monomers. The poly(VBA-co-AMAP) monolithic column showed good separation performance towards various polar compounds under different chromatographic conditions based on the π-interaction, hydrophobic and hydrogen bonding interactions provided by 4-vinylbenzoic acid functional monomer. Read More

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Single Co Atoms Implanted into N-Doped Hollow Carbon Nanoshells with Non-Planar Co-N-1-O Sites for Efficient Oxygen Electrochemistry.

Inorg Chem 2021 May 6. Epub 2021 May 6.

State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, P. R. China.

Facile synthesis of cost-effective carbon-supported Co single atoms (Co-SAs) exhibits huge potential applications in energy storage and conversion devices. We here report the implantation of Co-SAs into hollow carbon spheres (Co-SAs-HCS) via a facile wet-chemistry strategy followed by controlled pyrolysis. Electron-rich histidine acted as a Lewis base effectively immobilizing Co (Lewis acid) via the electrostatic effect and hydrogen bonds, thus achieving the scalable synthesis of Co-SAs-HCS. Read More

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Disaccharide Residues are Required for Native Antifreeze Glycoprotein Activity.

Biomacromolecules 2021 May 6. Epub 2021 May 6.

Max Planck Institute for Polymer Research, 55128 Mainz, Germany.

Antifreeze glycoproteins (AFGPs) are able to bind to ice, halt its growth, and are the most potent inhibitors of ice recrystallization known. The structural basis for AFGP's unique properties remains largely elusive. Here we determined the antifreeze activities of AFGP variants that we constructed by chemically modifying the hydroxyl groups of the disaccharide of natural AFGPs. Read More

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Screening of hydrogen bonding interactions by a single layer graphene.

Nanoscale 2021 May 6;13(17):8098-8106. Epub 2021 Apr 6.

School of Polymer Science and Polymer Engineering, University of Akron, Akron, OH 44325, USA.

A single layer of graphene when transferred to a solid substrate has the ability to screen or transmit interactions from the underlying substrate, which has direct consequences in applications of this 2D material to flexible electronics and sensors. Previous reports using a multitude of techniques present contradictory views on graphene's ability to screen or transmit van der Waals (vdW) and polar interactions. In the present study, we use interface-sensitive spectroscopy to demonstrate that a single layer graphene is opaque to hydrogen bonding interactions (a subset of acid-base interactions), answering a question that has remained unresolved for a decade. Read More

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The design of anion-π interactions and hydrogen bonds for the recognition of chloride, bromide and nitrate anions.

Phys Chem Chem Phys 2021 May 6. Epub 2021 May 6.

Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, Franca, SP, Brazil.

The role of anions in several biochemical processes has given rise to enormous interest in the identification/exploration of compounds with the potential ability to recognize anions. Here, an anthracene-squaramide conjugated compound, O2C4[NH(C14H10)][(NH(C6H6)], has been modified through the substitutions (i) H → F and (ii) H → OH at the anthracene and benzene rings to improve the capabilities of these structures for recognizing chloride, bromide, and nitrate anions. Through an energy decomposition analysis method, the recognition of the anions is chiefly identified as a non-covalent process. Read More

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Fundamental photophysics of isomorphic and expanded fluorescent nucleoside analogues.

Chem Soc Rev 2021 May 6. Epub 2021 May 6.

Laboratoire de Bioimagerie et Pathologies, UMR 7021, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France.

Fluorescent nucleoside analogues (FNAs) are structurally diverse mimics of the natural essentially non-fluorescent nucleosides which have found numerous applications in probing the structure and dynamics of nucleic acids as well as their interactions with various biomolecules. In order to minimize disturbance in the labelled nucleic acid sequences, the FNA chromophoric groups should resemble the natural nucleobases in size and hydrogen-bonding patterns. Isomorphic and expanded FNAs are the two groups that best meet the criteria of non-perturbing fluorescent labels for DNA and RNA. Read More

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Characterization and structure-activity relationship of novel umami peptides isolated from Thai fish sauce.

Food Funct 2021 May 6. Epub 2021 May 6.

College of Food Science and Engineering, Bohai University. National & Local Joint Engineering Research Center of Storage, Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products, Jinzhou, Liaoning 121013, China.

Fish sauce has a prominent umami flavor. In this study, umami peptides were isolated, purified and identified from Thai fish sauce, and their structure-activity relationships were analyzed. Six novel umami peptides were characterized and verified by using sensory evaluation and a electronic tongue. Read More

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evidences on filarial cystatin as a putative ligand of human TLR4.

J Biomol Struct Dyn 2021 May 6:1-17. Epub 2021 May 6.

Integrative Biochemistry & Immunology Laboratory, Department of Animal Science, Kazi Nazrul University, Asansol, West Bengal, India.

Cystatin is a small molecular weight immunomodulatory protein of filarial parasite that plays a pivotal role in downregulating the host immune response to prolong the survival of the parasite inside the host body. Hitherto, this protein is familiar as an inhibitor of human proteases. However, growing evidences on the role of cystatin in regulating inflammatory homeostasis prompted us to investigate the molecular reasons behind the explicit anti-inflammatory trait of this protein. Read More

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Tuning Ligand-coordinated Single Metal Atoms on TiO2 and their Dynamic Response during Hydrogenation Catalysis.

ChemSusChem 2021 May 5. Epub 2021 May 5.

Indiana University, Department of Chemistry, 800 E. Kirkwood Ave., 47405, Bloomington, UNITED STATES.

Ligand-coordinated supported catalysts (LCSCs) are of growing interest for heterogeneous single-atom catalysis. We investigate the effect of the choice of organic ligand on the activity and stability of TiO2-supported single-atom Pt-ligand catalysts for ethylene hydrogenation. The activity of these catalysts shows a significant dependence on the choice of ligand and also correlates with coordination number for Pt-ligand and Pt-Cl ̶. Read More

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Light-induced difference FTIR spectroscopy of primate blue-sensitive visual pigment at 163 K.

Biophys Physicobiol 2021 13;18:40-49. Epub 2021 Feb 13.

Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan.

Structural studies of color visual pigments lag far behind those of rhodopsin for scotopic vision. Using difference FTIR spectroscopy at 77 K, we report the first structural data of three primate color visual pig-ments, monkey red (MR), green (MG), and blue (MB), where the batho-intermediate (Batho) exhibits photo-equilibrium with the unphotolyzed state. This photo-chromic property is highly advantageous for limited samples since the signal-to-noise ratio is improved, but may not be applicable to late intermediates, because of large structural changes to proteins. Read More

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February 2021

Identification of a novel inhibitor of SARS-CoV-2 3CL-PRO through virtual screening and molecular dynamics simulation.

PeerJ 2021 13;9:e11261. Epub 2021 Apr 13.

Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh.

Background: The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has ravaged lives across the globe since December 2019, and new cases are still on the rise. Peoples' ongoing sufferings trigger scientists to develop safe and effective remedies to treat this deadly viral disease. While repurposing the existing FDA-approved drugs remains in the front line, exploring drug candidates from synthetic and natural compounds is also a viable alternative. Read More

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Synthesis and crystal structure of -poly[[tetra-μ-acetato-copper(II)]-μ-6-eth-oxy-,-bis-[2-(pyridin-2-yl)eth-yl]-1,3,5-triazine-2,4-di-amine].

Acta Crystallogr E Crystallogr Commun 2021 Mar 26;77(Pt 3):319-323. Epub 2021 Feb 26.

Department of Chemistry, Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA.

The title compound, [Cu(CHNO)(CHO)] , was obtained reaction of copper(II) acetate with the coordinating ligand, 6-eth-oxy-,-bis-[2-(pyridin-2-yl)eth-yl]-1,3,5-triazine-2,4-di-amine. The crystallized product adopts the monoclinic 2/ space group. The metal core exhibits a paddle-wheel structure typical for dicopper tetra-acetate units, with triazine and pyridyl nitro-gen atoms from different ligands coordinating to the two axial positions of the paddle wheel in an asymmetric manner. Read More

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Syntheses and structures of two benzoyl amides: 2-chloro-4-eth-oxy-3,5-dimeth-oxy--(3-oxo-cyclo-hex-1-en-1-yl)benzamide and 2-chloro--(5,5-dimethyl-3-oxo-cyclo-hex-1-en-1-yl)-4-eth-oxy-3,5-di-meth-oxy-benzamide.

Acta Crystallogr E Crystallogr Commun 2021 Mar 26;77(Pt 3):314-318. Epub 2021 Feb 26.

Department of Natural Sciences, Bowie State University, 14000 Jericho Park Road, Bowie, MD 20715-9465, USA.

The first title benzoyl amide, CHClNO (), crystallizes in the monoclinic space group 2/ with = 4 and the second, CHClNO (), also crystallizes in 2/ with = 8 (' = 2), thus there are two independent mol-ecules in the asymmetric unit. In , the phenyl ring makes a dihedral angle of 50.8 (3)° with the amide moiety with the C=O group on the same side of the mol-ecule as the C-Cl group. Read More

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