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heterocyclic amines

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https://www.readbyqxmd.com/read/29143992/teaching-old-compounds-new-tricks-ddq-photocatalyzed-c-h-amination-of-arenes-with-carbamates-urea-and-n-heterocycles
#1
Somnath Das, Palani Natarajan, Burkhard König
The C-H amination of benzene derivatives was achieved using DDQ as photocatalyst and BocNH₂ as the amine source under aerobic conditions and visible light irradiation. Electron-deficient and electron-rich benzenes react as substrates with moderate to good product yields. The amine scope of the reaction comprises Boc-amine, carbamates, pyrazoles, sulfonimide and urea. Preliminary mechanistic investigations indicate a charge transfer complex between the amine and DDQ as essential intermediate of the reaction...
November 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29143469/reaction-of-thiocarbonyl-fluoride-formed-from-difluorocarbene-with-amines
#2
Ji-Chang Xiao, Jiao Yu, Jinhong Lin
The reaction of thiocarbonyl fluoride generated from difluorocarbene with various amines under mild conditions is described. Secondary amines, primary amines, and o-phenylenediamines are converted to thiocarbamoyl fluorides, isothiocyanates, and difluoromethylthiolated heterocycles, respectively. Thiocarbamoyl fluorides were further transformed into trifluoromethylated amines using a one-pot process. As thiocarbonyl fluoride is generated in situ and is rapidly fully converted in one pot under mild conditions, no special safety precautions are needed...
November 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29141567/discovery-of-thiazole-based-bis-heterocyclic-system-for-anti-inflammatory-potential
#3
Amit S Tapkir, Sohan S Chitlange, Ritesh P Bhole
BACKGROUND: We have developed a new series of 36 substituted thiazole derivatives prepared via reaction of substituted benzothiazole-2-amine with substituted phenacyl bromide Objective: This study was aimed to develop and successfully evaluate anti-inflammatory activity of substituted thiazole derivatives. METHOD: A new series of 36 substituted thiazole derivatives was synthesized and derivatives were characterized by analytical and spectrometric methods like IR, MS, and 1H NMR...
November 14, 2017: Anti-inflammatory & Anti-allergy Agents in Medicinal Chemistry
https://www.readbyqxmd.com/read/29141143/michael-michael-addition-reactions-promoted-by-secondary-amine-thiourea-stereocontrolled-construction-of-barbiturate-fused-tetrahydropyrano-scaffolds-and-pyranocoumarins
#4
Jing Zhang, Guohui Yin, Yuchao Du, Ziqi Yang, Yang Li, Ligong Chen
Bifunctional secondary amine-thiourea organocatalysts were successfully applied in the stereocontrolled synthesis of barbiturate fused tetrahydropyrano scaffold. As compared with the generally used tertiary amine-thiourea organocatalysts, they exhibited Bifunctional secondary amine-thiourea organocatalysts were successfully applied in the stereocontrolled synthesis of barbiturate-fused tetrahydropyrano scaffolds. Compared with typically used tertiary amine-thiourea organocatalysts, the developed catalysts exhibited excellent catalytic performance in the domino Michael-Michael reaction between N,N'-dimethylbarbituric acid and Morita-Baylis-Hillman acetates of nitroalkenes to yield pharmaceutically important heterocycles in good yields with excellent enantioselectivities...
November 15, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29139160/assessing-the-ligand-properties-of-nhc-stabilized-phosphorus-i-cations
#5
Justin F Binder, Stephanie C Kosnik, Charles Lloyd Bergstrom Macdonald
The isolation and full characterization of a series of cationic metal carbonyl complexes bearing an N-heterocyclic carbene-stabilized phosphorus(I) ligand are reported. Specifically, the mononuclear coordination complexes [LM(CO)₅][BPh₄] (M = Cr, Mo, W), [LFe(CO)₄][BPh₄] and the dinuclear complexes [LMn₂(CO)₈][BPh₄] and [LCo₂(CO)₆][BPh₄], where L = [bis(1,3,4,5-tetramethylimidazol-2-ylidene)phosphanide]+, have all been isolated in the solid state and structurally confirmed by single crystal X-ray diffraction...
November 14, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29136796/a-multi-purpose-tool-for-food-inspection-simultaneous-determination-of-various-classes-of-preservatives-and-biogenic-amines-in-meat-and-fish-products-by-lc-ms
#6
Luciano Molognoni, Heitor Daguer, Leandro Antunes de Sá Ploêncio, Juliano De Dea Lindner
This paper describes an innovative fast and multipurpose method for the chemical inspection of meat and fish products by liquid chromatography-tandem mass spectrometry. Solid-liquid extraction and low temperature partitioning were applied to 17 analytes, which included large bacteriocins (3.5kDa) and small molecules (organic acids, heterocyclic compounds, polyene macrolides, alkyl esters of the p-hydroxybenzoic acid, aromatic, and aliphatic biogenic amines and polyamines). Chromatographic separation was achieved in 10min, using stationary phase of di-isopropyl-3-aminopropyl silane bound to hydroxylated silica...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29132210/organocatalytic-visible-light-enabled-snar-of-heterocyclic-thiols-a-metal-free-approach-to-2-aminobenzoxazoles-and-4-aminoquinazolines
#7
Eakkaphon Rattanangkool, Mongkol Sukwattanasinitt, Sumrit Wacharasindhu
The direct amination reaction of heterocyclic thiols has been developed in the presence of the nonhazardous photocatalyst Rose Bengal under irradiation of visible light. The reaction provides a straightforward approach to pharmaceutically and synthetically useful to 2-aminobenzoxazole and 4-aminoquinazoline derivatives from the corresponding heterocyclic thiols with amines in good to excellent yields. Our photochemical reaction can be successfully adapted into continuous flow reactor which is applicable for large scale chemical industry...
November 14, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29125741/achieving-molecular-complexity-via-stereoselective-multiple-domino-reactions-promoted-by-a-secondary-amine-organocatalyst
#8
Pankaj Chauhan, Suruchi Mahajan, Dieter Enders
In the last two decades, organocatalysis has emerged as an intensively investigated and rapidly growing area of research facilitating many known and many new transformations to provide efficient novel entries to complex molecules of high stereochemical purity. The organocatalysts have not only shown their efficiency for catalyzing the reactions in which one bond is formed, but they have also been effectively exploited in various versions of one-pot reactions. Domino reactions are one of the most important classes of one-pot reactions, where the target structure can be obtained in one pot without changing any reaction conditions while each reaction occurs as a consequence of the intermediates generated in previous steps...
November 10, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29094189/comparative-developmental-toxicity-of-a-comprehensive-suite-of-polycyclic-aromatic-hydrocarbons
#9
Mitra C Geier, Anna C Chlebowski, Lisa Truong, Staci L Massey Simonich, Kim A Anderson, Robert L Tanguay
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that occur in complex mixtures. Several PAHs are known or suspected mutagens and/or carcinogens, but developmental toxicity data is lacking for PAHs, particularly their oxygenated and nitrated derivatives. Such data are necessary to understand and predict the toxicity of environmental mixtures. 123 PAHs were assessed for morphological and neurobehavioral effects for a range of concentrations between 0.1 and 50 µM, using a high throughput early-life stage zebrafish assay, including 33 parent, 22 nitrated, 17 oxygenated, 19 hydroxylated, 14 methylated, 16 heterocyclic, and 2 aminated PAHs...
November 1, 2017: Archives of Toxicology
https://www.readbyqxmd.com/read/29083150/in-search-of-deeper-blues-trans-n-heterocyclic-carbene-platinum-phenylacetylide-as-a-dopant-for-phosphorescent-oleds
#10
James D Bullock, Amin Salehi, Charles J Zeman, Khalil A Abboud, Franky So, Kirk S Schanze
A trans-N-heterocyclic carbene (NHC) platinum(II) acetylide complex bearing phenyl acetylene ligands (NPtPE1) has been synthesized via the Hagihara reaction in 64% yield. The complex features spectrally narrow deep blue emission with a phosphorescence quantum yield (0.30) and lifetime (∼10 μs) in the solid state. The modest quantum yield and lifetime make NPtPE1 a candidate for incorporation into an organic light emitting diode (OLED). Prototype devices exhibited a maximum EQE of 8% with CIE (0.20,0.20)...
November 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29073479/acetonitrile-extraction-coupled-with-uhplc-ms-ms-for-the-accurate-quantification-of-17-heterocyclic-aromatic-amines-in-meat-products
#11
Yan Yan, Shuang Zhang, Guan-Jun Tao, Feng-Hui You, Jie Chen, Mao-Mao Zeng
This study proposed a simple and accurate acetonitrile extraction pretreatment method coupled with ultrahigh-performance liquid chromatography with tandem mass spectrometry for the simultaneous determination of 17 heterocyclic aromatic amines (HAAs) in meat products. With this new method, all 17 HAAs, including 11 polar and 6 nonpolarHAAs, were simultaneously extracted by acetonitrile and purified by one-step Oasis MCX cartridge purification. Compared with two different improved reference methods, the acetonitrile method could obtain higher recoveries (in the range of 42...
October 9, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29069497/harmane-induced-selective-dopaminergic-neurotoxicity-in-c-elegans
#12
Shreesh Raj Sammi, Zeynep Sena Agim, Jason R Cannon
Parkinson's disease (PD) is a debilitating neurodegenerative disease. While numerous exposures have been linked to PD etiology, causative factors for most cases remain largely unknown. Emerging data on the neurotoxicity of heterocyclic amines suggest that this class of compounds should be examined for relevance to PD. Here, using C. elegans as a model system, we tested whether harmane exposure produced selective toxicity to dopamine neurons that is potentially relevant to PD. Harmane is a known tremorigenic β-carboline (a type of heterocyclic amine) found in cooked meat, roasted coffee beans, and tobacco...
October 23, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/29061827/lactoperoxidase-an-antimicrobial-milk-protein-as-a-potential-activator-of-carcinogenic-heterocyclic-amines-in-breast-cancer
#13
Ishfaq Ahmad Sheikh, Essam Hussain Jiffri, Mohammad Amjad Kamal, Ghulam Md Ashraf, Mohd Amin Beg
BACKGROUND: Lactoperoxidase (LPO) is an antimicrobial protein secreted from mammary, salivary and other mucosal glands. It is an important member of heme peroxidase enzymes and the primary peroxidase enzyme present in breast tissues. In addition to the antimicrobial properties, LPO has been shown to be associated with breast cancer etiology. Heterocyclic amines, an important class of environmental and dietary carcinogens, have been increasingly associated with breast cancer etiology. Heterocyclic amines undergo activation in breast tissue as a result of oxidation by LPO...
November 2017: Anticancer Research
https://www.readbyqxmd.com/read/29053265/step-economical-photoassisted-diversity-oriented-synthesis-sustaining-cascade-photoreactions-in-oxalyl-anilides-to-access-complex-polyheterocyclic-molecular-architectures
#14
Dmitry M Kuznetsov, Andrei G Kutateladze
Atom- and step-economy in photoassisted diversity-oriented synthesis (DOS) is achieved with a versatile oxalyl linker offering rapid access to complex alkaloid mimics in very few experimentally simple steps: (i) it allows for fast tethering of the photoactive core to the unsaturated pendants, especially important in the case of (hetero)aromatic amines-essentially a one-pot reaction with no isolation of intermediates; (ii) the α-dicarbonyl tether acts as a chromophore enhancer, extending the conjugation chain and facilitating the "harvest" of the lower energy photons for the primary and secondary photoreactions; (iii) it enhances the quantum yield of intersystem crossing (ISC), i...
November 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29053003/detoxification-of-cancerogenic-compounds-by-lactic-acid-bacteria-strains
#15
Zhao Lili, Wei Junyan, Zhao Hongfei, Zhu Baoqing, Zhang Bolin
Carcinogens in food are an important issue that threat people's health right now. Lactic acid bacteria (LAB) strains as well-known probiotics have shown numerous perspectives in being used as a good food additive to confront cancerogenic compounds in recent years. Some LAB strains can remove cancerogenic compounds from medium environment via direct physical binding and avoid re-pollution of poisonous secondary metabolites which are generated from degradation of cancerogenic compounds. This article presents a whole overview of the physical-binding of LAB strains to such common cancerogenic compounds existed in food and feed environments as mycotoxins, polycyclic aromatic hydrocarbons (PAHs), heterocyclic amines (HAs) and pthalic acid esters (PAEs)...
October 20, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/29052416/n-heterocycle-forming-amino-carboperfluoroalkylations-of-aminoalkenes-by-using-perfluoro-acid-anhydrides-mechanistic-studies-and-applications-directed-toward-perfluoroalkylated-compound-libraries
#16
Shintaro Kawamura, Kento Dosei, Elena Valverde, Kiminori Ushida, Mikiko Sodeoka
This work describes a practical and efficient method for synthesizing a diverse array of perfluoroalkylated amines, including N-heterocycles, to afford perfluoroalkylated chemical libraries as potential sources of drug candidates, agrochemicals, and probe molecules for chemical-biology research. Perfluoro acid anhydrides, which are commonly used in organic synthesis, were employed as a perfluoroalkyl source for intramolecular amino- and carbo-perfluoroalkylations of aminoalkenes, affording perfluoroalkylated N-heterocycles, including: aziridines, pyrrolidines, benzothiazinane dioxides, indolines, and hydroisoquinolinones...
November 1, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29045154/enantioselective-1-3-dipolar-cycloaddition-of-methyleneindolinones-with-%C3%AE-diazomethylphosphonate-to-access-chiral-spiro-phosphonylpyrazoline-oxindoles-catalyzed-by-tertiary-amine-thiourea-and-1-5-diazabicyclo-4-3-0-non-5-ene
#17
Nan Huang, Liangliang Zou, Yungui Peng
A methodology to access chiral 3,3'-spiro-phosphonylpyrazoline oxindoles via an asymmetric 1,3-dipolar cycloaddition reaction of substituted methyleneindolinones with α-diazomethylphosphonate in the catalysis of tertiary amine thiourea and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) has been established. This method exhibits high functional group compatibility, where a wide range of methyleneindolinones with various substituents and heterocyclic rings are accommodated by this reaction. The resulting chiral 3,3'-spiro-phosphonylpyrazoline oxindoles can be further transformed into spiro-phosphonylcyclopropane oxindoles by ring contraction...
October 18, 2017: Organic Letters
https://www.readbyqxmd.com/read/29043821/in-situ-generation-of-a-regio-and-diastereoselective-hydroaminoalkylation-catalyst-using-commercially-available-starting-materials
#18
Peter M Edwards, Laurel L Schafer
The design of an easy to use catalyst system for the regio- and diastereoselective intermolecular hydroaminoalkylation of alkenes with secondary amines is reported. The method utilizes commercially available ligands and tantalum starting materials, and does not require the isolation of air and water sensitive organometallic complexes. The in situ prepared catalyst is active toward a variety of secondary amine substrates, including those with ethyl substituents which yield α- and β-alkylated amines as a single diastereomer...
October 18, 2017: Organic Letters
https://www.readbyqxmd.com/read/29037029/coupling-n-h-deprotonation-c-h-activation-and-oxidation-metal-free-c-sp-3-h-aminations-with-unprotected-anilines
#19
Christopher J Evoniuk, Gabriel Dos Passos Gomes, Sean P Hill, Satoshi Fujita, Kenneth Hanson, Igor V Alabugin
An intramolecular oxidative C(sp(3))-H amination from unprotected anilines and C(sp(3))-H bonds readily occurs under mild conditions using t-BuOK, molecular oxygen and N,N-dimethylformamide (DMF). Success of this process, which requires mildly acidic N-H bonds and an activated C(sp(3))-H bond (BDE < 85 kcal/mol), stems from synergy between basic, radical, and oxidizing species working together to promote a coordinated sequence of deprotonation: H atom transfer and oxidation that forges a new C-N bond. This process is applicable for the synthesis of a wide variety of N-heterocycles, ranging from small molecules to extended aromatics without the need for transition metals or strong oxidants...
October 31, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29027801/palladium-0-catalyzed-carbonylative-one-pot-synthesis-of-n-acylguanidines
#20
Linda Åkerbladh, Luke S Schembri, Mats Larhed, Luke R Odell
A convenient synthetic strategy toward N-acylguanidines via a sequential one-pot multicomponent carbonylation/amination reaction has been developed. The compounds were readily obtained via an N-cyanobenzamide intermediate formed from the Pd(0)-catalyzed carbonylative coupling of cyanamide and aryl iodides or bromides. Subsequent amination with a large variety of amines provided the final N-acylguanidines, with the overall formation of one C-C and two C-N bonds, in moderate to excellent yields. The substrate scope was found to be wide and the methodology was used to produce over 50 compounds, including 29 novel molecules...
October 27, 2017: Journal of Organic Chemistry
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