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heterocyclic amines

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https://www.readbyqxmd.com/read/28738621/determining-heterocyclic-aromatic-amines-in-aqueous-samples-a-novel-dispersive-liquid-liquid-micro-extraction-method-based-on-solidification-of-floating-organic-drop-and-ultrasound-assisted-back-extraction-followed-by-uplc-ms-ms
#1
Romina Canales, María Guiñez, Cristian Bazán, Mario Reta, Soledad Cerutti
A novel dispersive liquid-liquid microextraction based on solidification of floating organic droplet combined with ultrasound assisted back extraction for the determination of four heterocyclic aromatic amines in natural water samples prior ultra high-performance liquid chromatography-tandem mass spectrometry was developed. The analytes were extracted from the water samples by a dispersive liquid-liquid microextraction procedure based on solidification of floating organic drop, which was performed by a mixture composed by a less dense than water extraction solvent, 1-undecanol, and a dispersive solvent, methanol...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28723092/microwave-assisted-synthesis-of-diversely-substituted-quinoline-based-dihydropyridopyrimidine-and-dihydropyrazolopyridine-hybrids
#2
Daniel Insuasty, Rodrigo Abonia, Braulio Insuasty, Jairo Quiroga, Kenneth K Laali, Manuel Nogueras, Justo Cobo
An efficient, catalyst-free and one-pot three-component procedure for the synthesis of novel and nitrogen rich dihydropyrido[2,3-d]pyrimidines and dihydro-1H-pyrazolo[3,4-b]pyridines bearing a quinoline pharmacophore fragment is provided. Reactions proceeded in DMF under microwave irradiation of three-component mixtures of formyl-quinoline derivatives, primary heterocyclic amines and cyclic 1,3-diketones. Interestingly, when conventional heating at reflux was used for the starting 5-amino-1-phenylpyrazole, the corresponding aromatized pyrazolopyridines were obtained as the main products...
July 19, 2017: ACS Combinatorial Science
https://www.readbyqxmd.com/read/28719728/robust-acenaphthoimidazolylidene-palladacycles-highly-efficient-catalysts-for-the-amination-of-n-heteroaryl-chlorides
#3
Tao Tu, Qinyue Deng, Yang Zhang, Haibo Zhu
A series of robust N-heterocyclic carbene palladacycles have been successfully developed, which exhibited high catalytic activity and selectivity toward the challenging amination of N-heteroaryl chlorides. Diverse primary and secondary amines are fully compatible with our new developed catalytic system. Remarkably, no double amination products could be detected when primary amines were utilized in our catalytic transformation. Furthermore, the protocol has been successfully extended to synthesize Rosiglitazone, a clinical drug for diabetes mellitus, highlighting its potential pharmaceutical feasibility...
July 18, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28714386/nitroisoxazolones-showing-diverse-chemical-behavior-a-useful-building-block-for-polyfunctionalized-systems
#4
Nagatoshi Nishiwaki
4-Nitroisoxazolin-5(2H)-one (nitroisoxazolone) has multiple functionalities embedded as the partial structures that include a nitroalkene, an enamine, a lactone, a N-O bond, and an α, β-unsaturated carbonyl moiety. These structural features facilitate versatile chemical transformations that lead to polyfunctionalized heterocycles that are not easily available by alternative methods. Anionic nitroisoxazolone readily undergoes ring opening to afford dianionic cyano-aci-nitroacetate. This dianionic reagent serves as a safe cyano(nitro)methylating agent to afford glutaronitriles and α-nitro-δ-keto nitriles that are precursors of polyfunctionalized isoxazolines, pyridines, and diazabicycliccompounds...
July 14, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28684984/new-tricks-of-well-known-aminoazoles-in-isocyanide-based-multicomponent-reactions-and-antibacterial-activity-of-the-compounds-synthesized
#5
Maryna V Murlykina, Maryna N Kornet, Sergey M Desenko, Svetlana V Shishkina, Oleg V Shishkin, Aleksander A Brazhko, Vladimir I Musatov, Erik V Van der Eycken, Valentin A Chebanov
The well-known aminoazoles, 3-amino-5-methylisoxazole and 5-amino-N-aryl-1H-pyrazole-4-carboxamides, were studied as an amine component in Ugi and Groebke-Blackburn-Bienaymé multicomponent reactions. The first example of an application of aminoazoles in an Ugi four-component reaction was discovered and novel features of a Groebke-Blackburn-Bienaymé cyclocondensation are established and discussed. The heterocycles obtained were evaluated for their antibacterial activity and several of them demonstrated a weak antimicrobial effect, but for most of the compounds a 30-50% increase in biomass of Gram-positive strains (mainly B...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28682400/interaction-of-organic-compounds-with-chondritic-silicate-surfaces-atomistic-insights-from-quantum-chemical-periodic-simulations
#6
Albert Rimola, Josep M Trigo-Rodríguez, Zita Martins
The interaction of 14 different probe organic molecules with the crystalline (010) forsterite Mg2SiO4 surface has been studied at quantum chemical level by means of B3LYP-D2* periodic simulations. The probe molecules are representatives of the class of soluble organic compounds found in carbonaceous meteorites, namely: aliphatic and aromatic hydrocarbons, alcohols, carbonyl compounds, amines, amides, nitrogen heterocycles, carboxylic and hydroxycarboxylic acids, sulfonic and phosphonic acids, amino acids, and carbohydrates...
July 6, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28679205/metabolism-of-food-borne-heterocyclic-aromatic-amines-by-lactobacillus-reuteri-dsm-20016
#7
Falco Beer, Felix Urbat, Jan Steck, Melanie Huch, Diana Bunzel, Mirko Bunzel, Sabine E Kulling
The heterocyclic aromatic amine (HAA) 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is converted into 7-hydroxy-5-methyl-3-phenyl-6,7,8,9-tetrahydropyrido[3',2':4,5]imidazo[1,2-a]pyrimidin-5-ium chloride (PhIP-M1) via a chemical reaction with 3-hydroxypropionaldehyde or acrolein derived from glycerol by reuterin producing gut bacteria. Because it is unknown whether this reaction is also relevant for other HAAs, seven food-borne HAAs (2-amino-9H-pyrido[2,3-b]indole (AαC), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethyl-3H-imidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 9H-pyrido[3,4-b]indole (norharman), and 1-methyl-9H-pyrido[3,4-b]indole (harman)) were anaerobically incubated with Lactobacillus reuteri DSM 20016 in the presence of glycerol...
July 5, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28671272/the-effects-of-different-spices-and-fat-types-on-the-formation-of-heterocyclic-aromatic-amines-in-barbecued-sucuk
#8
Kübra Ünal, Mustafa Karakaya, Fatih Öz
BACKGROUND: Sucuk is one of the popular traditional Turkish meat products. The aim of this research was to evaluate the effects of different spices (clove, 0.2%; cinnamon, 0.5%) and animal fat types (beef fat, tallow, subcutaneous and tail fat) on the formation of heterocyclic aromatic amine (HCA) in barbecued sucuk. RESULTS: While 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) could not be detected in the any of the samples, 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx) (up to 0...
July 3, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28666384/gut-microbial-transformation-of-the-dietary-imidazoquinoxaline-mutagen-meiqx-reduces-its-cytotoxic-and-mutagenic-potency
#9
Jianbo Zhang, Michael T Empl, Clarissa Schwab, Mostafa I Fekry, Christina Engels, Mirjam Schneider, Christophe Lacroix, Pablo Steinberg, Shana J Sturla
The diverse community of microbes present in the human gut has emerged as an important factor for cancer risk, potentially by altering exposure to chemical carcinogens. In the present study, human gut bacteria were tested for their capacity to transform the carcinogenic heterocyclic amine 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). Eubacterium hallii, Lactobacillus reuteri, and Lactobacillus rossiae were able to convert MeIQx to a new microbial metabolite characterized on the basis of high resolution mass spectrometry and NMR as 9-hydroxyl-2,7-dimethyl-7,9,10,11-tetrahydropyrimido[2',1':2,3]imidazo[4,5-f]quinoxaline (MeIQx-M1), resulting from conjugation with activated glycerol...
June 28, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28666059/%C3%AE-unsubstituted-pyrroles-by-nhc-catalyzed-three-component-coupling-direct-synthesis-of-a-versatile-atorvastatin-derivative
#10
Mirco Fleige, Frank Glorius
A practical one-pot cascade reaction protocol provides direct access to valuable 1,2,4-trisubstituted pyrroles. The process involves an N-heterocyclic carbene (NHC)-catalyzed Stetter-type hydroformylation using glycolaldehyde dimer as a novel C1 building-block, followed by a Paal-Knorr condensation with primary amines. The reaction makes use of simple and commercially available starting-materials and catalyst, an important feature regarding applicability and utility. Low catalyst loading under mild reaction conditions afforded a variety of 1,2,4-substituted pyrroles in a transition-metal free reaction with high step economy and good yields...
June 30, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28664729/synthesis-of-pyrrolotriazoloisoquinoline-frameworks-by-intramolecular-cu-mediated-or-free-radical-arylation-of-triazoles
#11
Liya D Funt, Olesya A Tomashenko, Ivan P Mosiagin, Mikhail S Novikov, Alexander F Khlebnikov
The cyclization of (2-bromophenyl)pyrrolyl-1,2,4-triazoles via copper-mediated intramolecular direct C-arylation of 1,2,4-triazoles was first accomplished under triazole-NHC control to give unknown fused heterocyclic skeletons, pyrrolo[3,2-c][1,2,4]triazolo[5,1-a] or [3,4-a]isoquinolines. The primary products underwent a triazole ring opening under the basic arylation conditions, providing N-(1H-pyrrolo[3,2-c]isoquinolin-5-yl)cyanamides. The formation of the cyanamides from isomeric pyrrolo[3,2-c][1,2,4]triazolo[3,4-a]isoquinolines involves, besides the triazole ring opening, the unusual migration of the cyano group...
July 12, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28661140/exploring-the-dynamics-of-the-photoinduced-ring-opening-of-heterocyclic-molecules
#12
Michael N R Ashfold, Matthew Bain, Christopher S Hansen, Rebecca A Ingle, Tolga N V Karsili, Barbara Marchetti, Daniel Murdock
Excited states formed by electron promotion to an antibonding σ* orbital are now recognized as key to understanding the photofragmentation dynamics of a broad range of heteroatom containing small molecules: alcohols, thiols, amines, and many of their aromatic analogues. Such excited states may be populated by direct photoexcitation, or indirectly by nonadiabatic transfer of population from some other optically excited state (e.g., a ππ* state). This Perspective explores the extent to which the fast-growing literature pertaining to such (n/π)σ*-state mediated bond fissions can inform and enhance our mechanistic understanding of photoinduced ring-opening in heterocyclic molecules...
July 12, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28657326/rh-ii-catalyzed-chemoselective-oxidative-amination-and-cyclization-cascade-of-1-arylethynyl-cycloalkyl-methyl-sulfamates
#13
Dong Pan, Yin Wei, Min Shi
A Rh(II)-catalyzed chemoselective oxidative amination and cyclization cascade of 1-(arylethynyl)cycloalkyl)methyl sulfamates has been presented. For a cyclopropyl or cyclobutyl moiety containing alkynyl sulfamates, the reactions underwent a metallonitrene-initiated alkyne oxidation along with cyclopropyl ring expansion or alkoxyl moiety migration to give cyclobutane-fused or methylenecyclobutane-containing heterocycles. In the case of a cyclopentyl or cyclohexyl moiety containing sulfamate, the reaction underwent a direct C-H bond insertion event to afford the corresponding nitrogen-containing heterocyclic product...
June 28, 2017: Organic Letters
https://www.readbyqxmd.com/read/28653129/cu-ii-complex-of-pyridine-based-polydentate-as-a-novel-efficient-and-highly-reusable-catalyst-in-c-n-bond-forming-reaction
#14
Hashem Sharghi, Saeideh Sepehri, Mahdi Aberi
In this paper, a highly reusable copper(II) complex of pyridine-based polydentate is able to efficiently catalyze a C-N bond-forming reaction under mild conditions. A variety of N-heterocyclic and amine compounds arylated with different aryl iodides, bromides, and chlorides produced N-substituted compounds in good to excellent yields. This methodology can be also used for the arylation of N-unsubstituted compounds using arylboronic acids under solvent-free conditions. All reactions are performed in short times under air, and the catalyst can be reused up to seven times...
June 26, 2017: Molecular Diversity
https://www.readbyqxmd.com/read/28649017/chiral-alkylated-aniline-as-a-noninvasive-fluorescence-sensor-spectroscopic-and-molecular-modeling-studies
#15
Bidisha Sengupta, Chirantan Sen Mukherjee, Sandipan Chakraborty, Maria Jones Muhammad, William Gladney, George Armstrong
Aniline, heterocyclic aromatic amines, and arylamines are known carcinogens. Recently aniline mustard has come into prominence as a novel anticancer agent. In this project, microwave irradiation has been used to synthesize an optically active alkylated aniline namely 2,6-dimethyl-4-(1-(p-tolyl)ethyl)aniline (abbreviated DMPA). The presence of quartet and doublet peaks in NMR and a single chromatogram in HPLC verified that the final product DMPA, prepared from the synthesis reactions, had no major impurities...
June 7, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28641002/mechanistic-study-of-smi2-h2o-and-smi2-amine-h2o-promoted-chemoselective-reduction-of-aromatic-amides-primary-secondary-tertiary-to-alcohols-via-aminoketyl-radicals
#16
Syed R Huq, Shicheng Shi, Ray Diao, Michal Szostak
Samarium(II) iodide-water and samarium(II) iodide-water-amine complexes have been recognized as valuable reagents for the selective generation of aminoketyl radicals from amides and derivatives. The resulting aminoketyl radicals can undergo reduction or reductive cyclization pathways, providing a powerful method for (i) direct synthesis of alcohols from amides by the challenging N-C bond scission and (ii) synthesis of nitrogen-containing heterocycles via polarity reversal of the amide bond. This report describes mechanistic investigation into samarium(II) iodide-water and samarium(II) iodide-water-amine-mediated generation of benzylic aminoketyl radicals from aromatic primary, secondary, and tertiary amides (benzamides)...
June 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28638656/crystal-structure-of-2-azido-1-3-bis-2-6-diiso-propyl-phen-yl-1-3-2-di-aza-phospho-lidine
#17
Alex J Veinot, Amber D Blair, Jason D Masuda
The title compound, C26H38N5P, was synthesized by reacting 2-chloro-1,3-bis-(2,6-diiso-propyl-phen-yl)-1,3,2-di-aza-phospho-lidine with sodium azide and a catalytic amount of lithium chloride in tetra-hydro-furan. The title compound is the first structurally characterized 2-azido-1,3,2-di-aza-phospho-lidine and exhibits a P atom in a trigonal pyramidal geometry. The azide P-N bond length of 1.8547 (16) Å is significantly longer than the P-N separations for the chelating di-amine [P-N = 1.6680 (15) and 1...
June 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28635286/utilization-of-an-active-site-mutant-receptor-for-the-identification-of-potent-and-selective-atypical-5-ht2c-receptor-agonists
#18
Joseph Carpenter, Ying Wang, Gang Wu, Jianxin Feng, Xiang-Yang Ye, Christian L Morales, Matthias Broekema, Karen A Rossi, Keith J Miller, Brian J Murphy, Ginger Yingzhe Wu, Sarah E Malmstrom, Anthony V Azzara, Philip M Sher, John M Fevig, Andrew Alt, Robert L Bertekap, Mary Jane Cullen, Timothy M Harper, Kimberly A Foster, Chiuwa Emily Luk, Qian Xiang, Mary F Grubb, Jeffrey A Robl, Dean A Wacker
Agonism of the 5-HT2C receptor represents one of the most well-studied and clinically-proven mechanisms for pharmacological weight reduction. Selectivity over the closely related 5-HT2A and 5-HT2B receptors is critical as their activation has been shown to lead to undesirable side-effects and major safety concerns. In this communication, we report the development of a new screening paradigm which utilizes an active site mutant D134A 5-HT2C receptor to identify atypical agonist structures. We additionally report the discovery and optimization of a novel class of non-basic heterocyclic amide agonists of 5-HT2C...
June 21, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28635251/molecular-adsorbates-switch-on-heterogeneous-catalysis-induction-of-reactivity-by-n-heterocyclic-carbenes
#19
Johannes B Ernst, Christian Schwermann, Gen-Ichi Yokota, Mizuki Tada, Satoshi Muratsugu, Nikos L Doltsinis, Frank Glorius
We report the N-heterocyclic carbene (NHC)-induced activation of an otherwise unreactive Pd/Al2O3 catalyst. Surface analysis techniques demonstrate the NHC being coordinated to the palladium particles and affecting their electronic properties. Ab initio calculations provide further insight into the electronic effect of the coordination with the NHC injecting electron density into the metal nanocluster thus lowering the barrier for bromobenzene activation. By this NHC modification, the catalyst could be successfully applied in the Buchwald-Hartwig amination of aryl chlorides, bromides, and iodides...
June 28, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28632937/synthesis-biological-evaluation-and-docking-studies-of-trans-stilbene-methylthio-derivatives-as-cytochromes-p450-family-1-inhibitors
#20
Marcin Wierzchowski, Zbigniew Dutkiewicz, Agnieszka Gielara-Korzańska, Artur Korzański, Anna Teubert, Artur Teżyk, Tomasz Stefański, Wanda Baer-Dubowska, Renata Mikstacka
Cytochromes P450 family 1 (CYP1) are responsible for the metabolism of procarcinogens, e.g. polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines. The inhibition of CYP1 activity is examined in terms of chemoprevention and cancer chemotherapy. We designed and synthesized a series of trans-stilbene derivatives possessing a combination of methoxy and methylthio functional groups attached in different positions to the trans-stilbene skeleton. We determined the effects of synthesized compounds on the activities of human recombinant CYP1A1, CYP1A2 and CYP1B1 and, to explain the variation of inhibitory potency of methoxystilbene derivatives and their methylthio analogs, we employed computational analysis...
June 20, 2017: Chemical Biology & Drug Design
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