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heterocyclic amines

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https://www.readbyqxmd.com/read/28937695/trinuclear-complexes-of-palladium-ii-with-chalcogenated-n-heterocyclic-carbenes-catalysis-of-selective-nitrile-primary-amide-interconversion-and-sonogashira-coupling
#1
Pooja Dubey, Sonu Gupta, Ajai K Singh
3-Methyl-1-(2-(phenylthio/seleno)ethyl)-1H-benzo[d]imidazol-3-ium iodide (L1/L2), a precursor of sulfated/selenated N-heterocyclic carbene, was synthesized by the reaction of benzimidazole with 1,2-dichloroethane followed by treatment with PhS/SeNa and MeI. The reaction of L1/L2 with Ag2O followed by treatment with [Pd(CH3CN)2Cl2] (metal to ligand ratio 3 : 2), i.e. transmetallation, resulted in trinuclear palladium(ii) complexes [Pd3(L1/L2-HI)2(CH3CN)Cl6] (1-2). The complexes were characterized with (1)H, (13)C{(1)H} and (77)Se{(1)H} NMR (2 only), elemental analyses, HR-MS and single-crystal X-ray diffraction...
September 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28933794/inhibitory-profiles-of-spices-against-free-and-protein-bound-heterocyclic-amines-of-roast-beef-patties-as-revealed-by-ultra-performance-liquid-chromatography-tandem-mass-spectrometry-and-principal-component-analysis
#2
Jing Chen, Zhiyong He, Fang Qin, Jie Chen, Dongsheng Cao, Fengxian Guo, Maomao Zeng
The effects of various levels of chili pepper, Sichuan pepper, and black pepper on the amounts of 17 heterocyclic amines (HAs) from seven categories of both free and protein-bound states in roast beef patties were assessed by ultra-performance liquid chromatography-tandem mass spectrometry combined with principal component analysis. Three groups of HA, including imidazopyridines (DMIP), imidazoquinoxalines (MeIQx and 4,8-MeIQx), and β-carbolines (norharman and harman), were detected and quantified in both their free and protein-bound states, whereas PhIP was detected only in its free state, and imidazoquinolines (IQ, IQ[4,5-b], and MeIQ), α-carbolines (AαC and MeAαC), and phenylpyridines (Phe-P-1) were detected only in their protein-bound states...
September 21, 2017: Food & Function
https://www.readbyqxmd.com/read/28933540/metal-complexes-with-a-hexadentate-macrocyclic-diamine-tetracarbene-ligand
#3
Taotao Lu, Chu-Fan Yang, Li-Yi Zhang, Fan Fei, Xue-Tai Chen, Zi-Ling Xue
A hexadentate macrocyclic N-heterocyclic carbene (NHC) ligand precursor (H4L)(PF6)4 containing four benzimidazolium and two secondary amine groups, has been synthesized and characterized. Coordination chemistry of this new macrocyclic diamine-tetracarbene ligand has been studied by the synthesis of its Ag(I), Au(I), Ni(II), and Pd(II) complexes. Reactions of (H4L)(PF6)4 with different equiv of Ag2O result in Ag(I) complexes [Ag(H2L)](PF6)3 (1) and [Ag2(H2L)](PF6)4 (2). A mononuclear Au(I) complex [Au(H2L)](PF6)3 (3) and a trinuclear Au(I) complex [Au3(H2L)(Cl)2](PF6) (4) are obtained by transmetalation of 1 and 2 with AuCl(SMe2), respectively...
September 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28926233/copper-i-catalyzed-regio-and-stereoselective-intramolecular-alkylboration-of-propargyl-ethers-and-amines
#4
Hiroaki Iwamoto, Yu Ozawa, Koji Kubota, Hajime Ito
The copper(I)-catalyzed regio- and stereoselective intramolecular alkylation of propargyl ethers and amines bearing an alkyl electrophilic moiety has been developed. The reaction showed high functional group tolerance and gave highly functionalized alkenylboronates bearing heterocyclic rings, which are versatile synthetic intermediates in organic chemistry. The borylation products can be transformed into multi-substituted alkenes through stereospecific transformations. Mechanistic studies showed that the chemo- and stereoselectivity of copper(I)-catalyzed borylation depends on the type of leaving group...
September 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28926053/catalytic-domino-amination-and-oxidative-coupling-of-gold-acetylides-and-isolation-of-key-vinylene-digold-intermediates-as-a-new-class-of-ditopic-n-heterocyclic-carbene-complexes
#5
Haifeng Chen, Jiwei Wang, Zejun Hu, Sheng Xu, Min Shi, Jun Zhang
A catalytic domino amination and oxidative coupling of in situ prepared gold acetylides has been developed for the synthesis of abnormal NHC (aNHC) gold complexes, and key vinylene digold intermediates are isolated and structurally characterized.
September 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28910106/stereoselective-and-regioselective-synthesis-of-heterocycles-via-copper-catalyzed-additions-of-amine-derivatives-and-alcohols-to-alkenes
#6
Sherry R Chemler, Shuklendu Karyakarte, Zainab M Khoder
This Perspective describes the development of a family of copper-catalyzed alkene difunctionalization reactions that enable stereoselective addition of amine derivatives and alcohols onto pendant unactivated alkenes to provide a range of valuable saturated nitrogen and oxygen heterocycles. 2-Vinylanilines and related substrates undergo alternative oxidative amination or allylic amination pathways and these reactions will also be discussed. The involvement of both polar and radical steps in the reaction mechanisms have been implicated...
September 14, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28901784/impact-of-maillard-reaction-products-on-nutrition-and-health-current-knowledge-and-need-to-understand-their-fate-in-the-human-digestive-system
#7
Nesreen ALJahdali, Franck Carbonero
The Maillard Reaction (MR) is a non-enzymatic chemical reaction which results in the linkage between the amino group of amino acids and the carbonyl group of reduced sugars. MR products (MRPs) are common components of processed foods, mainly as a result of heating, especially in the Western diet. MRPs are classified as into three stages: initial, intermediate, and final stages, indicative of increased complexity and size, incurring different flavor, aroma, and texture. MRPs presence is known to reduce the nutritional quality of foods, particularly by reducing protein digestibility...
September 13, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28898845/the-transformation-pathways-of-nitrogen-in-sewage-sludge-during-hydrothermal-treatment
#8
Xiuzheng Zhuang, Yanqin Huang, Yanpei Song, Hao Zhan, Xiuli Yin, Chuangzhi Wu
Hydrothermal treatment (HT) has been proved as a significant pretreatment in decreasing emissions of NOX pollutants from thermochemical utilization of sewage sludge (SS) derived solid fuel. This study aims to investigate the denitrification of HT and the redistribution of nitrogen (N) in different products so as to speculate the comprehensive pathway of N transformation during hydrothermal process. Results found that only 20% of N remained in hydrochar, whereas the rest of N (nearly 80%) was transformed into other phase...
September 1, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28892363/exploiting-a-beast-in-carbenoid-chemistry-development-of-a-straightforward-direct-nucleophilic-fluoromethylation-strategy
#9
Giovanna Parisi, Marco Colella, Serena Monticelli, Giuseppe Romanazzi, Wolfgang Holzer, Thierry Langer, Leonardo Degennaro, Vittorio Pace, Renzo Luisi
The first direct and straightforward nucleophilic fluoromethylation of organic compounds is reported. The tactic employs a "fleeting" lithium fluorocarbenoid (LiCH2F) generated from commercially available fluoroiodomethane. Precise reaction conditions were devel-oped for generation and synthetic exploitation of such a labile spe-cies. The versatility of the strategy is showcased in about 50 examples involving a plethora of electrophiles. Highly valuable chemicals such as fluoro alcohols, fluoro amines and fluoromethylated oxy-genated heterocycles could be prepared in very good yields through a single synthetic operation...
September 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28891572/novel-spirocyclic-systems-via-multicomponent-aza-diels-alder-reaction
#10
Sabin Llona-Minguez, Adam Throup, Emilie Steiner, Molly Lightowler, Sandra Van der Haegen, Evert Homan, Lars Eriksson, Pål Stenmark, Annika Jenmalm-Jensen, Thomas Helleday
Here we present a two-step diastereoselective methodology building on a multicomponent aza-Diels-Alder reaction. Using previously unexplored cyclic ketones, heterocyclic amines and cyclopentadiene derivatives, we obtained novel spiro-heterocyclic frameworks at the interphase between "drug-like" molecules and natural products.
September 11, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28886889/anti-influenza-activity-of-diazaadamantanes-combined-with-monoterpene-moieties
#11
Evgeniy Suslov, Vladimir V Zarubaev, Alexander V Slita, Konstantin Ponomarev, Dina Korchagina, Daniel M Ayine-Tora, Jóhannes Reynisson, Konstantin Volcho, Nariman Salakhutdinov
The antiviral activity of several diaza-adamantanes containing monoterpenoid moieties against a rimantadine-resistant strain of the influenza A/Puerto Rico/8/34 (H1N1) virus was studied. Hetero-adamantanes containing monoterpene moieties at the aminal position of the heterocycle were found to exhibit lower activity compared to compounds with a diaza-adamantane fragment and a monoterpene moiety linked via an amino group at the 6-position of the hetero-adamantane ring. The highest selectivity index (a ratio of the 50% cytotoxic concentration to the 50% inhibitory concentration) out of 30 was observed for compound 8d, which contains a citronellal monoterpenoid moiety...
September 1, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28883490/in-vitro-exposure-of-simulated-meat-cooking-fumes-to-assess-adverse-biological-effects
#12
Bijay Kumar Poudel, Jungwook Choi, Jae Hong Park, Kyung-Oh Doh, Jeong Hoon Byeon
The heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is considered as a human carcinogenic or mutagenic compound that is produced from the co-condensation of creatinine and amino acids as meats cook at high temperatures. The cooking of meats at high temperatures produces fumes, and these fumes can be suspended as aerosols via the vapor-to-particle (or -droplet) process in a temperature gradient field. Size distributions of the aerosols included a significant portion of nano- and submicron-sized particles, and these can be directly deposited in the lungs and on skin by particle transport phenomena near cooking areas...
September 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28879062/a-modeling-approach-to-evaluate-the-balance-between-bioactivation-and-detoxification-of-meiqx-in-human-hepatocytes
#13
Victorien Delannée, Sophie Langouët, Nathalie Théret, Anne Siegel
BACKGROUND: Heterocyclic aromatic amines (HAA) are environmental and food contaminants that are potentially carcinogenic for humans. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is one of the most abundant HAA formed in cooked meat. MeIQx is metabolized by cytochrome P450 1A2 in the human liver into detoxificated and bioactivated products. Once bioactivated, MeIQx metabolites can lead to DNA adduct formation responsible for further genome instability. METHODS: Using a computational approach, we developed a numerical model for MeIQx metabolism in the liver that predicts the MeIQx biotransformation into detoxification or bioactivation pathways according to the concentration of MeIQx...
2017: PeerJ
https://www.readbyqxmd.com/read/28876951/enantioselective-synthesis-of-1-2-diamines-containing-tertiary-and-quaternary-centers-through-rhodium-catalyzed-dykat-of-racemic-allylic-trichloroacetimidates
#14
Edward T Mwenda, Hien M Nguyen
The amination of racemic secondary and tertiary allylic trichloroacetimidates possessing β-nitrogen substituents and proximal nitrogen-containing heterocycles, via chiral diene-ligated rhodium-catalyzed dynamic kinetic asymmetric transformations (DYKAT), provides branched allylic 1,2-diamines with high enantioselectivity. The catalytic system can be applied to the synthesis of 1,2-diamines possessing two contiguous stereocenters with excellent diastereoselectivity. Furthermore, the nitrogen-containing heterocycles suppress competing vinyl azirdine formation, allowing for the high enantioselective syntheses of 1,2-diamines possessing tertiary and quaternary centers...
September 6, 2017: Organic Letters
https://www.readbyqxmd.com/read/28876944/polycyclic-azetidines-and-pyrrolidines-via-palladium-catalyzed-intramolecular-amination-of-unactivated-c-sp3-h-bonds
#15
Jie Zhao, Xiao-Jing Zhao, Pei Cao, Ji-Kai Liu, Bin Wu
A novel strategy to construct complex polycyclic nitrogen-containing heterocycles from aliphatic amines via picolinamide-assisted palladium-catalyzed C-H bond activation reaction was reported. The reaction exhibits broad substrate scope for the synthesis of various azabicyclic scaffolds, including azetidines and tropane-class alkaloids. Application of this method to naturally occurring (-)-cis-myrtanylamine, an unprecedented type of carbon-carbon bond activation, in which the electron-pair involved initiates an intramolecular "SN2-like" displacement of a cyclopalladium-fragment from a tertiary center, is described...
September 6, 2017: Organic Letters
https://www.readbyqxmd.com/read/28873528/inhibitory-effects-of-sichuan-pepper-zanthoxylum-bungeanum-and-sanshoamide-extract-on-heterocyclic-amine-formation-in-grilled-ground-beef-patties
#16
Maomao Zeng, Junhui Wang, Mengru Zhang, Jing Chen, Zhiyong He, Fang Qin, Zhimin Xu, Dongsheng Cao, Jie Chen
This study evaluated the inhibitory effects of Sichuan pepper (Zanthoxylum bungeanum) and sanshoamide extract on the formation of heterocyclic amines (HAs) in grilled beef patties. The following major HAs were detected and quantified: imidazopyridine (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, PhIP), imidazoquinoxalines (2-amino-3-methyl-3H-imidazo[4,5-f]quinoxaline, IQx; 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, MeIOx; 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline, 4,8-DiMeIQx) and β-carbolines (9H-pyrido[3,4-b]indole, norharman; 1-methyl-9H-pyrido[3,4-b]indole, harman)...
January 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/28853481/formation-of-hydrazones-and-stabilized-boron-nitrogen-heterocycles-in-aqueous-solution-from-carbohydrazides-and-ortho-formylphenylboronic-acids
#17
Han Gu, Tak Ian Chio, Zhen Lei, Richard J Staples, Jennifer S Hirschi, Susan Bane
A recent addition to the suite of fast bioorthogonal reactions combines hydrazines and hydroxylamines with ortho-carbonyl substituted phenylboronic acids. Carbohydrazides are easily incorporated into biomolecules, making them appealing substrates in these reactions. Here we show that simple alkyl carbohydrazides form a single product with ortho-formylphenylboronic acid in an organic solvent and in the solid state. The solution structures of the products formed from the carbohydrazides in buffered aqueous solution, however, are markedly different from those identified in the organic solvent and solid state...
September 20, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28821745/metabolomics-and-genomics-combine-to-unravel-the-pathway-for-the-presence-of-fragrance-in-rice
#18
Venea Dara Daygon, Mariafe Calingacion, Louise C Forster, James J De Voss, Brett D Schwartz, Ben Ovenden, David E Alonso, Susan R McCouch, Mary J Garson, Melissa A Fitzgerald
Since it was first characterised in 1983, 2-acetyl-1-pyrroline (2AP) has been considered to be the most important aroma compound in rice. In this study, we show four other amine heterocycles: 6-methyl, 5-oxo-2,3,4,5-tetrahydropyridine (6M5OTP), 2-acetylpyrrole, pyrrole and 1-pyrroline, that correlate strongly with the production of 2AP, and are present in consistent proportions in a set of elite aromatic rice varieties from South East Asia and Australia as well as in a collection of recombinant inbred lines (RILs) derived from indica Jasmine-type varieties, Australian long grain varieties (temperate japonica) and Basmati-type rice (Grp V)...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28803433/distribution-of-serum-levels-of-persistent-organic-pollutants-heterocyclic-aromatic-amine-theoretical-intake-and-nutritional-cofactors-in-a-semi-rural-island-population
#19
Daniel Carrizo, Sarah F Brennan, Olivier P Chevallier, Jayne Woodside, Kevin M Cooper, Marie M Cantwell, Geraldine Cuskelly, Christopher T Elliott
Persistent organic pollutant (POP) exposure is strongly associated with negative health effects in humans. Heterocyclic aromatic amines (HAAs) are formed during high temperature cooking of foods (i.e. meat and fish). Human exposure to HAA is through food consumption and from similar food groups to POPs. A study of serum samples for POPs in a non-occupational exposed population (n = 149, age range 18-80 years, recruited in 2012) and comparison with estimated HAA daily intake calculations based on food diaries were undertaken...
August 12, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28795799/the-tetraarylpyrrolo-3-2-b-pyrroles-from-serendipitous-discovery-to-promising-heterocyclic-optoelectronic-materials
#20
Maciej Krzeszewski, Dorota Gryko, Daniel T Gryko
Progress in organic optoelectronics requires compounds possessing a suitable combination of photophysical and electronic properties. Another key constraint encompasses the availability of feasible, and hopefully scalable, synthetic procedures for preparing the molecular scaffolds of interest. A multicomponent reaction of aromatic aldehydes, aromatic amines, and butane-2,3-dione that was discovered in 2013 gives straightforward access to previously unavailable 1,2,4,5-tetraarylpyrrolo[3,2-b]pyrroles. These dyes are examples of heteropentalenes-a class of 10-π-electron aromatic compounds...
August 10, 2017: Accounts of Chemical Research
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