Search

Recycled crumb rubber (CR) is rich in compounds with unrecognized toxic potency; this study aims at the development of an analytical method that would allow identification and quantification of a very wide range of organic compounds extractable from the complex rubber matrix. The analytical set-up includes target analysis of polycyclic aromatic hydrocarbons (PAHs) and methyl-PAHs and suspect screening of raw extracts to tentatively identify primary organic compounds present, but not included in the standard target analysis of recycled rubber, followed by analytical method development and target analysis of identified compounds. Analyzed samples included weathered and new CR originating from football turf granulates, rubber mats, and end-of-life car tires (ELTs). The developed analytical method involves sonication extraction, followed by solid phase extraction (SPE) fractionation that enables simple and efficient separation of analytes with broad polarity scale. The application of SPE fractionation resolves coelution problems and simplifies the chromatograms. This analytical approach allowed to identify and quantify 46 sample specific compounds, including several heterocyclic PAHs like 2-methylthiobenzothiazole, benzonapthothiophenes, benzonaphthofuranes and aromatic amines like diphenylamine and N-phenyl-2-naphthylamine, which to our knowledge were not determined before. The PAHs concentrations determined in CR tiles purchased in Dutch and Spanish shops exceed the EU limits for articles marketed for use by the public. Furthermore, sets of methylated PAHs, dibenzothiazoles and aromatic amines were identified and quantified, and several other compounds were tentatively identified. The obtained results stress the need for expanding the list of target compounds analyzed in CR and the need for longitudinal studies on weathering processes taking place in CR., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The research focused on the photolysis of ortho‐ and para‐substituted aryl azides and the preparation of 2‐arylamino‐substituted azepines. The best results were achieved in 1,4‐dioxane for ortho‐substituted azides and in ethanol for para‐substituted azides, respectively. It was found that reactions with arylamines, which have electron‐donating groups, typically produce higher yields of heterocycles than those with electron‐withdrawing groups. [ABSTRACT FROM AUTHOR]

Since heterocyclic compounds offer a wide spectrum of biological functions, they have primarily been produced thus far. A significant significance for Schiff base exists in the biological area. As a result of these reviews, we produced a new line of N2, N4-bis(4-{[(substitutedphenyl)methylidene]amino}phenyl)-N6-(4-methyl phenyl)-1,3,5-triazine-2,4,6-triamine derived from N²-(4-methylphenyl)-N4,N6-bis(4-aminophenyl)-1,3,5-triazine-2,4,6-triamine with various substituted aromatic aldehydes in having the presence of ethanol. IR and NMR spectrum data, as well as element analysis were used to describe the title compounds. All substances were evaluated for antimicrobial activity using the Cup-Borer method. [ABSTRACT FROM AUTHOR]

The current assignment depicts the structure of recent quinoline derivatives. This method begins with the structure of imine derivatives through the condensation reaction of ethyl 2-aminobenzoate with various substituted aliphatic aldehydes and ketones in the existence of sodium hydroxide as a catalyst. While the second step includes the intra-cyclization process of the imine compounds in presence of a base like tertiary butoxide that resolute installs the hydroxyl-group on the bicyclic skeleton and aromatic amines. The molecular docking program Flare V4.0 was applied to investigate the biological activities of divers produced compounds against E.coli bacteria. Spectral data support the compounds of each the recent outputs acquired during this assignment. [ABSTRACT FROM AUTHOR]

1,3,5-Triazine derivatives are an important class of heterocyclic compounds with great interest in medicine, agriculture, electronics, and other industries. In this article, we report on the synthesis of 4-aryl-6-alkylamino/piperidinyl-1,3,5-triazine-2-amines via one-pot, multi-component reactions of cyanamide, aromatic aldehydes and an amine (piperidine, aqueous dimethylamine and butylamine) using microwave irradiation under neat conditions. The structure of the obtained products was confirmed by 1H-NMR and13CNMR spectra, mass spectrometry and, in two cases, X-ray diffraction. [ABSTRACT FROM AUTHOR]

Cyclization–aromatization of enamines is a powerful method for the establishment of aza-aromatic cycles. We report herein the development of a simple and practical [3 + 3] aldol cyclization–aromatization of β,γ-dioxobutanoate with amines for the synthesis of p-aminophenols. Reactions with primary, secondary, benzyl and aryl amines all proceeded smoothly under mild reaction conditions, without catalysts and additives. Sensitive functionalities and heterocycles such as alcohol, ether, halogen, carboxylic acid, alkyne, pyridine, imidazole and free (N–H) indole, which could interfere with metal-, or acid-mediated processes, were well tolerated. The high degree of compatibility and practicability of this method is demonstrated by the late-stage cyclization–aromatization of structurally complex drug molecules. [ABSTRACT FROM AUTHOR]

Herein, we describe the synthesis of a wide variety of imines through oxidative coupling of alcohols and aromatic amines catalyzed by Mn complexes bearing N^N triazole ligands. A wide variety of imines in excellent yields (up to 99%) have been prepared. Mn-based catalysts proved to be highly efficient and versatile, allowing for the first time the preparation of several imines containing N-based heterocycles. [ABSTRACT FROM AUTHOR]

Pyrrole derivatives with C(2)-aryl substituents are an important and widespread class of heterocyclic compounds. Their synthesis can be accomplished using several strategic variants which usually entail either protection of the N–H functionality followed by the arylation, or a direct arylation. Although direct arylation is a preferable process due to a reduced number of synthetic steps, it often requires vigorous conditions or challenging reagents. To this synthetic repertoire, we add a novel method that is based on the dual role of the arylating agent. It serves as the nitrogen protecting group while also being involved in the arylation step. Deprotection as a final stage is carried out simultaneously utilising amines as reacting components. This approach ensures relatively mild conditions and exclusive C(2) selectivity yielding 2-arylpyrroles with the amide functionality. While aromatic amines are not suitable partners under studied conditions, most likely due to lower nucleophilicity, aliphatic amines, either primary or secondary, afford products in good yields. [ABSTRACT FROM AUTHOR]

Bacon usually have a high salt content. Excessive intake of salt could cause a harm to human health. Heterocyclic aromatic amines (HAAs) are carcinogenic and mutagenic heterocyclic compounds formed by the reactions of precursor substances at high temperature. This study investigated the influence of different levels of NaCl on the HAA contents and quality characteristics of bacon. Moisture, aw, L* value, b* value, thiobarbituric acid‐reactive substance (TBARS), and carbonyl content increased significantly with a decrease in the NaCl concentration of the brine (p < 0.05). There were no significant differences between treatments for a* value, pH, creatine content, sensory redness, bitterness, or off‐odor (p > 0.05). Sensory evaluation showed that saltiness in bacon increased significantly with increased NaCl concentrations in brine. The increased NaCl concentrations decreased the total HAAs in fried bacon (p < 0.05). Moreover, the nonpolar HAA contents in bacon were higher than the polar HAA contents; salt concentration mainly affected the nonpolar HAA content. In summary, salt content had a significant influence on the HAA content and the quality characteristic of bacon. [ABSTRACT FROM AUTHOR]

An efficient access to the novel 5-(het)arylamino-1,2,3-triazole derivatives has been developed. The method is based on Buchwald–Hartwig cross-coupling reaction of 5-Amino or 5-Halo-1,2,3-triazoles with (het)aryl halides and amines, respectively. As result, it was found that palladium complex [(THP-Dipp)Pd(cinn)Cl] bearing expanded-ring N-heterocyclic carbene ligand is the most active catalyst for the process to afford the target molecules in high yields. [ABSTRACT FROM AUTHOR]

Substituted undecahydrido-closo-dodecaborates [B12H11NR2]2− have potential use in materials and drugs, but have presented a synthetic challenge. Microwave-assisted palladium-catalyzed amination of iodo-dodecaborate [B12H11I]2− allows mild and reproducible formation of B–N bonds with aromatic amines, HN-containing heteroaromatics, and amides. The reaction allows general access to amides, reproducible reactions to dodecaborate-substituted anilines, and, for the first time, the substitution of dodecaborate with HN-containing heterocycles. [ABSTRACT FROM AUTHOR]

Herein we report the use of spinel cobalt ferrite nanoparticles as an efficient and selective catalyst for the mono N‐alkylation of aryl and hetero aryl amines with various aromatic and aliphatic alcohols. Based on our experiments, the optimum condition for good to excellent yield were observed with alcohol (1.0 mmol), aniline (1.2 mmol), KOH (0.5 equiv), and CoFe2O4 nanocatalyst (10 mol%) in toluene at 130 °C in 24 hours. Further control experiment studies revealed that the reaction does not proceed in the absence of the catalyst or a strong base. This magnetically recyclable nanocatalyst does not require any ligands and is easily synthesized at low temperature. The reutilization of the recovered catalyst in a fresh reaction gave good to excellent yield. The experiment results strongly suggest a borrowing hydrogen pathway for N‐alkylation under our standard conditions. The utility of these nanocatalysts was also demonstrated for the dehydrogenative synthesis of heterocycles like indole and quinolines. [ABSTRACT FROM AUTHOR]

Isatin (1H-indole-2,3-dione) and its analogs are an important class of heterocyclic compounds. N-benzyl isatins and Schiff bases of isatin analogs have been reported to demonstrate a variety of biological activities. This work illustrates the synthesis of new N-benzylisatin Schiff bases and studies their biological activity. Firstly, Isatin and its analogs; 5-methoxyisatin, 5-fluoroisatin reacted with benzyl iodide to obtain N- benzylated derivatives of isatins 2(a-c). Secondly, these compounds were reacted with different amines (sulphanilamide and 4- methyl sulphonyl aniline) separately, to obtain Schiff bases compounds 3(a-c) and 4(a-c), respectively. The synthesized compounds were characterized by using FT-IR and 1HNMR spectroscopy. The synthesized Schiff bases 3(a-c) and 4(a-c) were examined for their in vitro antimicrobial activity using different Gram-positive bacteria, Gram-negative bacteria, and Candida albicans as fungi. The obtained results were compared with standard drugs: amoxicillin, ciprofloxacin, and fluconazole. All the compounds show no antifungal activity at any concentrations used, while most of them show moderate antibacterial activity at concentration 5mg/mL toward most bacteria except Klebsiella pneumonia. [ABSTRACT FROM AUTHOR]

3‐Amino‐substituted saturated nitrogen heterocycles are an important subclass of β‐diamines, appearing in a number of clinical agents. Herein, we report a unified approach to these products based upon the regioselective photoredox‐mediated hydroamination of enecarbamates. The amine coupling partner can encompass diverse amine types under a single set of reaction conditions, including primary alkyl amines, ammonia, aryl and heteroaryl amines, and N−H heterocycles. The method enables the synthesis of a wide range of pharmaceutically relevant building blocks. [ABSTRACT FROM AUTHOR]

The first synthesis of eight-membered N-containing heterocycles by oxidative bicyclization/ring extension of arylacetylenes and aryl amines has been achieved. This protocol uses arylacetylene as an unusual two-carbon synthon by incorporating the two parts of the cracked C≡C bond into the final product, which provides a new method for using arylacetylenes as two-carbon synthons and further enriches C≡C bond cleavage methodology. Moreover, this multi-component reaction can provide diverse fused elegant eight-membered N-heterocycles under mild conditions with wide substrate scopes. [ABSTRACT FROM AUTHOR]

The effects of wheat fiber (1 and 2%) and the mixture of xanthan and guar gums (0.5%; 4:1) incorporations in beef patties on the levels of formed polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) were evaluated. In this regard, the samples were stored at − 18 °C during different storage times (days 0, 45, and 90) and then were grilled at 175 °C for 5 min. At day 0, a significant (P < 0.05) difference in the formation of PAHs and HCAs among treated beef patties and control samples was noted. The formation of carcinogenic compounds at day 0 was reduced while fiber and gums together were added. The highest reduction in PAHs and HCAs levels among treatments was related to benzo [b] fluorantene (36–42%) and 2-amino-3-methyl-imidazo [4, 5-f] quinoline (60–74%), respectively. Also, the frozen storage of samples for 45 and 90 days significantly (P < 0.05) caused an increase and decrease in the PAHs and in HCAs levels, respectively. Therefore, the incorporation the combination of wheat fiber (2%), xanthan and guar gums (0.5%) can be suggested as a promising strategy to reduce the levels of PAHs and HCAs in beef patties. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of highly functionalized piperidines via one-pot domino reaction of β-ketoesters, aromatic aldehydes, and aromatic amines was reported. This multicomponent coupling was catalyzed by TMSI in methanol at room temperature, giving desired substituted pyridines in moderate to good yields. [ABSTRACT FROM AUTHOR]

The comparison of D index with HOMHED gave a good correlation (R2= 0.8221). However, a modification of D index, namely D', where the number of cycles involved in the tested molecule is substituted by the ratio between the number of atoms involved in π orbitals in the tested molecule and in reference molecule, gave a better correlation with a larger number of compounds (R2=0.8819), The correlation of D' with calculated HOMHED for pentatomic heterocyclic compounds did not give a unique correlation but a series of possible correlations. This behavior depends on the parameters used for the calculation of HOMHED that allow some negative values. In fact, the comparison of D' with NICS for selected pentatomic heterocycles gave good correlation. Good correlations were observed also in the comparison of D' with HOMHED and NICS for antiaromatic compounds. [ABSTRACT FROM AUTHOR]

In the present study, β-cyclodextrin-based nanosponges were prepared by reaction of β-cyclodextrin with dicarbonyl imidazole as a crosslinker agent. The synthesized polycarbonate nanosponge was characterized by FT-IR spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer–Emmett–Teller. The catalytic activity of β-cyclodextrin-based nanosponges was successfully tested in the one-pot three-component condensation of kojic acid, aromatic aldehydes and various aromatic amines. The superiority of this new strategy is short reaction times, high yields and utilizing of biodegradable and nontoxic nanocatalyst. [ABSTRACT FROM AUTHOR]

Formation of N−N bonds may offer an original approach to various nitrogen‐containing heterocycles with numerous applications. For this purpose, we found that readily available heteroaromatic amines are appropriate substrates for providing an efficient and innovative approach for the formation of N−N bonds in the presence of iodine (III) reagent in very mild conditions. This method makes it possible to synthesize nitrogen rich triazapentalene derivatives exhibiting fluorescent properties, inaccessible with existing approaches. [ABSTRACT FROM AUTHOR]

The safety of doner kebab as a traditional Middle East tasty food can threaten via the formation of dangerous compounds such as heterocyclic aromatic amines during heat process. In this regard, the current investigation was devoted to measuring of 4 HAAs (2‐amino‐3,4‐dimethylimidazo[4,5‐f]quinoline (MeIQ), 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline (MeIQx), 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP), and 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ)) in doner kebab samples with an innovative microextraction technique combined with high‐performance liquid chromatography. The limit of detection was in the range of 4.8 and 5.3 ng/g, while relative standard deviations were between 6.5% and 8.3%, and recoveries were calculated in the range of 89%–97%. The most and the least total mean values of HAA levels were 13.30 ng/g for MeIQx and 5.0 ng/g for IQ. The proposed method showed a high capability to extract trace amount of HAAs from a complex matrix such as doner kebab. Also, this technique is easy, high sensitive, selective, accurate and efficient. [ABSTRACT FROM AUTHOR]

In the selective N-arylation of amines or azoles with aryl halides-, methyl-α- d -glucopyranoside (MG) was found to function as a green ligand of copper powder. In addition, nitrogen heterocyclic amine compounds can also undergo the N-arylation coupling with heterocyclic aryl chlorides. This process allows access to a variety of aromatic amines and aryl azoles under mild reaction conditions, has good tolerance, and proceeds in moderate to high yield. [ABSTRACT FROM AUTHOR]

• Thiocarbonyl fluoride generated in situ from difluorocarbene acts as a thiocarbonyl source for cyclization. • The cyclization of X-H substituted amines provides imidazolidine-, oxazolidine- and thiazolidine-2-thiones. • The N H bond in products remains intact in the reactions involving the generation of difluorocarbene. Difluorocarbene has served as a versatile intermediate in organic synthesis. The transformation of difluorocarbene into thiocarbonyl fluoride, which was discovered by us previously, can be developed as a synthetic tool for the cyclization of vicinal X-H substituted amines to provide various five-membered heterocycles. However, aryl amines are required to be used and difluoromethylation of the N H bond or a newly generated S-H bond cannot be suppressed. Herein we describe the use of thiocarbonyl fluoride generated in situ as a thiocarbonyl source for the cyclization of vicinal X-H substituted alkyl amines (X = N , O, S) to provide imidazolidine-2-thiones, oxazolidine-2-thiones and thiazolidine-2-thiones. The use of alkyl amines constructs different heterocycles with those obtained from aryl amines. The free N H bond remains intact without being difluoromethylated. Described herein is the use of thiocarbonyl fluoride generated in situ from difluorocarbene as a thiocarbonyl source for the cyclization of vicinal X-H (X = N , O, or S) substituted amines to provide imidazolidine-2-thiones, oxazolidine-2-thiones and thiazolidine-2-thiones. [Display omitted] [ABSTRACT FROM AUTHOR]

1-Substituted 5-oxopyrrolidine-3-carboxylic acids were prepared via cyclization of 2-methylenesuccinic acid with aliphatic, aromatic, and heterocyclic amines. The synthesized compounds possessed analgesic and antihypoxic effects of varying strength. The analgesic activity was slightly greater for compounds with an aromatic or heterocyclic radical in the 1-position. [ABSTRACT FROM AUTHOR]

Heterocyclic aromatic amines (HAAs) produced during heat processing in meat samples are introduced as chemical toxicants with hazardous effect on human body. In this study, we applied an advanced, simple, efficient and sensitive analytical procedure based on microwave-assisted extraction and low density solvent/dispersive liquid–liquid microextraction coupled with high-performance liquid chromatography for the determination of four kinds of HAAs (2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)) in barbecued meat samples for the first time. The parameters affected on microextraction method including type and volume of extraction and disperser solvents, salt percent and PH were optimized using response surface design. The dynamic linear range was 1–1000 ng g−1. The coefficient of determination was higher than 0.982, relative standard deviations were between 3.7 and 8.1%. The recoveries in tree levels (10, 50 and 100 ng g−1) were obtained 89–101.5%. Detection limits were between 0.25 and 0.71 ng g−1. Offered technique is sensitive, selective‚ quick and precise. The most concentration of HAAs determined in barbecued meat samples was for IQ 1250 ng g−1 and the lowest amount is also related to IQ type 25 ng g−1. This proposed method presents proper concentration factors and detection limits for determination of HAAs in different barbecued meat samples. [ABSTRACT FROM AUTHOR]

Some new tetrazole derivatives were prepared by the reaction between the prepared azomethine compounds I6-I10 with sodium azide in anhydrous tetrahydrofuran (THF) with a few drops of distilled water and under reflux conditions. Azomethine compounds were prepared by thermal condensation reactions of aromatic aldehydes with primary aromatic amines. The prepared compounds (tetrazole derivatives) were screened for their antibacterial activity (by disc diffusion method). Compound I6 is the most active derivative that has recorded a significantly (p<0.01) stronger influence to inhibit the growth of Candida zeylanoides with an average zone of inhibition of 26.0 mm. Derivatives I7 and I9 showed the lowest zone of inhibition of 8.0 mm against Candida zeylanoides. This study may be helpful in designing more potential anticandidal agents for therapeutic use in the future. [ABSTRACT FROM AUTHOR]

An effective and practical protocol for the CuI‐catalyzed Ullmann‐type N‐arylation of azoles/amines with aryl halides is reported. The key strategy is the employment of CH2 linker N,O‐bidentate ligands, especially N‐(4‐thiazolylmethyl)morpholine N‐oxide, as superior supporting ligands. The highly efficient C−N coupling reactions between various azoles/amines and aryl halides bearing different functional groups can be achieved under CuI/N‐(4‐thiazolylmethyl)morpholine N‐oxide catalytic system, affording a variety of N‐arylated products. The use of cheap copper(I) salt and readily available N,O‐bidentate ligands make this procedure more attractive for synthesis of valuable functionalized nitrogen‐containing heterocyclic compounds. [ABSTRACT FROM AUTHOR]

Uncaging strategies that use near‐infrared wavelengths can enable the highly targeted delivery of biomolecules in complex settings. Many methods, including an approach we developed using cyanine photooxidation, are limited to phenol‐containing payloads. Given the critical role of amines in diverse biological processes, we sought to use cyanine photooxidation to initiate the release of aryl amines. Heptamethine cyanines substituted with an aryl amine at the C4′ position undergo only inefficient release, likely due electronic factors. We then pursued the hypothesis that the carbonyl products derived from cyanine photooxidation could undergo efficient β‐elimination. After examining both symmetrical and unsymmetrical scaffolds, we identify a merocyanine substituted with indolenine and coumarin heterocycles that undergoes efficient photooxidation and aniline uncaging. In total, these studies provide a new scheme—cyanine photooxidation followed by β‐elimination—through which to design photocages with efficient uncaging properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Different types of HAAs. • Formation mechanism and toxicology effect of HAAs. • Several groups of food matrices which containing HAAs. • Sample preparation and analytical techniques for monitoring and determination of HAAs. Abstract Heterocyclic aromatic amines (HAAs) are defined as a major class of poisonous compounds formed from proteinaceous foods during heat processing and flavour-forming. These toxicants have detrimental effects on the human body and eventually bring about mutagenicity and carcinogenicity. Owing to the presence of HAAs at a marginal level in the intricate tissue of food and their interactivity, an effective sample preparation should be employed to extract these controversial chemicals from the food matrix. For separation and detection of HAAs, advanced extraction methods and instrumental techniques have been applied. According to the type of sample preparation, sensitivity of the experiment, laboratory conditions and available facilities, the choice of analytical equipment will be different. In this review, various cooked food samples containing HAAs and heat processing of them have been listed. Also, sample pre-treatment and analytical techniques that have been applied to determine HAAs are discussed. [ABSTRACT FROM AUTHOR]

Considering pteridine as a worthy structure for improving probes of magnificent therapeutic potentials, some new pteridine conjugates were synthesized by aminomethylation of benzopteridinethione with a variety of primary aromatic amines and formaldehyde solution (37%) through the Mannich reaction. The proposed mechanism of formation of the synthesized compounds was discussed, and the structure of the newly synthesized compounds was elucidated on the basis of their IR, 1H NMR, 13C NMR, mass spectral, and elemental analyses. Furthermore, some selected compounds were evaluated in vitro for their antimicrobial activities; the preliminary data stated that the majority of the tested compounds exhibited significant antimicrobial activity. Analogues 22, 23, 20, 19, 24, and 15 were found to be the most potent against all the tested microorganisms. [ABSTRACT FROM AUTHOR]

A new copper‐catalyzed protocol for the intermolecular anti‐Markovnikov addition of arylamines or heterocycles to terminal and unsymmetrical 1,2‐disubstituted vinylarenes has been developed. The direct hydroamination is catalyzed by a readily available N‐heterocyclic carbene‐based copper complex and KOt‐Bu, and the use of MeOH as an additive enhances the reactivity. The method provides a broad range of new and versatile amine compounds bearing various functional groups in good to excellent yields. [ABSTRACT FROM AUTHOR]

Abstract In this study we investigated the genotoxic potential of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, (PhIP); 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline, (IQ); 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline, (MeIQx) and 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (DiMeIQx) on human freshly isolated peripheral blood mononuclear cells (PBMC) by the comet assay. The preventive ability of three different phenolic extracts derived from olive (O-PE), virgin olive oil (OO-PE) and olive leaf (OL-PE) on PhIP induced DNA damage was also investigated. PhIP and IQ induced a significant DNA damage at the lowest concentration tested (100 μM), while the genotoxic effect of MeIQx and DiMeIQx become apparent only in the presence of DNA repair inhibitors Cytosine b-D-arabinofuranoside and Hydroxyurea (AraC/HU). The inclusion of metabolic activation (S9-mix) in the culture medium increased the genotoxicity of all HCAs tested. All three phenolic extracts showed an evident DNA damage preventive activity in a very low concentration range (0.1–1.0 μM of phenols) which could be easily reached in human tissues "in vivo" under a regular intake of virgin olive oil. These data further support the observation that consumption of olive and virgin olive oil may prevent the initiation step of carcinogenesis. The leaf waste could be an economic and simple source of phenolic compounds to be used as food additives or supplements. Highlights • PhIP and IQ induced a significant DNA damage at a low concentration tested on PBMC. • MeIQx and DiMeIQx were genotoxic only in the presence of DNA repair inhibitors Cytosine b-D-arabinofuranoside and Hydroxyurea. • The metabolic activation (S9-mix) increased the genotoxicity of all HCAs tested. • Phenolic extracts prevented the PhIP induced DNA damage at low concentration reached in humans consuming virgin olive oil. [ABSTRACT FROM AUTHOR]

Efficient and versatile catalytic systems were developed for the N-methylation of both aliphatic and aromatic primary amines using methanol as the methylating agent. Iridium complexes bearing an Nheterocyclic carbene (NHC) ligand exhibited high catalytic performance for this type of transformation. For aliphatic amines, selective N,N-dimethylation was achieved at low temperatures (50-90 °C). For aromatic amines, selective N-monomethylation and selective N,N-dimethylation were accomplished by simply changing the reaction conditions (presence or absence of a base with an appropriate catalyst). These findings can be used to develop methods for synthesizing useful amine compounds having N-methyl or N,N-dimethyl moieties. [ABSTRACT FROM AUTHOR]

Data from National Health and Nutrition Examination Survey for US population aged ≥ 6 years for 2013-2014 were used to analyze data for four heterocyclic aromatic amines (HCAA), namely 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhlP), harman, and norharman. Data were analyzed separately for children aged 6-11 years (N = 416), adolescents aged 12-19 years (N = 475), adults aged 20-64 years (N = 1913), and seniors aged ≥ 65 years (N = 458). Adult males had lower concentrations of AαC and harman than adult females (1.44 vs. 2.22 pg/mL for AαC, p < 0.01 and 136.8 vs. 163.2 pg/mL for harman, p = 0.04). Racial/ethnic differences were observed in the adjusted concentrations of HCAAs. For adults, adjusted concentrations of HCAAs were lower for non-Hispanic Asians and Hispanics as compared to non-Hispanic blacks and whites. For example for AαC, the adjusted concentrations for non-Hispanic Asians, Hispanics, non-Hispanic blacks and whites were 1.16, 2.00, 2.37, and 2.16 pg/mL respectively. Adjusted concentrations of AαC were found to be lower among nonsmokers as compared to smokers for adolescents (0.34 vs. 1.32 pg/mL, p < 0.01), adults (0.40 vs. 7.91 pg/mL, p < 0.01), and seniors (0.30 vs. 4.29 pg/mL, p < 0.01). For both harman and norharman, adult nonsmokers had lower adjusted concentrations than smokers (125.7 vs. 177.6 pg/mL, p < 0.01 for harman, 296.1 vs. 421.6 pg/mL, p < 001, for norharman). Exposure to environmental tobacco smoke was found to be associated with higher concentrations of AαC among adolescents (p = 0.01) and adults (p = 0.01) and for harman (p = 0.01) and norharman (p = 0.01) among seniors. In conclusion, concentrations of selected HCAAs can be several fold higher among smokers as compared to nonsmokers and gender as well as race/ethnicity also affect the observed concentrations of HCAA. [ABSTRACT FROM AUTHOR]

Polyfunctionalized heterocyclic compounds have an important role in the drug discovery process and analysis of drugs in late development. Piperidines and their analogues have received attention owing to their biological activities, because of the importance of these heterocycle compounds, there is still a need to improve the ways for green synthesis of these compounds. In this study, lactic acid was applied as a green and efficient catalyst for the one-pot five-component synthesis of highly substituted piperidines from the reaction between aromatic aldehydes, aromatic amines, and b-ketoester at ambient temperature. This methodology has a number of advantages such as: use of easy access and green catalyst, short reaction times, high yields, and easy work-up (just simple filtration). [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Heterocyclic aromatic amines (HAAs) have been considered as carcinogenic and mutagenic chemicals generated during thermal processing of protein‐rich foods that can be inhibited by some flavonoids. Free radical scavenging is a major characteristic of flavonoids. RESULTS: The half‐maximal inhibitory concentration (IC50) values of nine flavonoids were determined by evaluating their capacity to inhibit 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline (MeIQx) and 2‐amino‐3,7,8‐trimethylimidazo[4,5‐f]quinoxaline (7,8‐DiMeIQx) formation in a model system. The results of the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) test validated that MeIQx and 7,8‐DiMeIQx formed via a free radical pathway. Electron spin resonance (ESR) spectroscopic analysis with spin trapping (α‐(4‐pyridyl N‐oxide)‐N‐tert‐butylnitrone (POBN) spin adduct, aN = 15.2 G and aH = 2.7 G) revealed that an alkoxy radical was the generated intermediate. The scavenging capacities of the nine flavonoids on alkoxy radicals were then evaluated based on the ESR spectra of the POBN spin adducts. CONCLUSION: The weak correlation between the alkoxy radical scavenging capacities and IC50 of the flavonoids suggested that their inhibitory activity against MeIQx and 7,8‐DiMeIQx formation operates by a more complex mechanism than simply scavenging alkoxy radicals. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

We describe herein the first examples of Povarov reaction of tetrasubstituted cyclopentadienones in the preparation of quinoline compounds. Polycyclic compounds bearing tetrahydro‐3H‐cyclopenta[c]quinoline and dihydro‐1H‐cyclopenta[c]naphtha[2,3‐h]quinoline moieties have been synthesized by one pot reaction of tetrasubstituted cyclopentadienones with N‐arylamines and formaldehyde in the presence of trifluoroacetic acid. The control of the regioselectivity was total as well with symmetrical and non symmetrical cyclopentadienones. The X‐ray structures of new quinolines were reported. [ABSTRACT FROM AUTHOR]

Heterocyclic aromatic amines (HAAs) are mutagenic and/or carcinogenic compounds formed in meat during processing. Dry meat products are known to have a high level of HAAs, while only few studies focused on the factors affecting the formation of HAAs. The aim of this study was to investigate the impact of different factors (manufacture methods, spices, breed and production place) on formation of HAAs in Chinese dried meat products. The results revealed that the manufacture methods impacted the contents of HAAs, roast non-deep frying production > natural air-drying method > deep frying method. Analysis of air-dried beef with different spices confirmed that spices inhibited HAAs formation. However, spices seemed to increase HAAs levels in air-dried yak samples. The total content of HAAs in dried product from Chinese yellow cattle was higher than that of other selected breeds (Aberdeen Angus cattle and Chinese yak). Beef jerky from Sichuan had higher HAAs contents than that from Inner Mongolia. Yak jerky from Sichuan had lower HAAs amounts than that from Qinghai. Overall, this study indicates that processing methods, spices, the breed and the place affected the HAAs levels in dried beef jerky products. However, additional studies are needed to determine the interaction of several factors. [ABSTRACT FROM AUTHOR]

We describe herein the palladium-catalyzed aminocarbonylation of nitrogen-containing heterocycles with aniline derivatives using molybdenum hexacarbonyl as a CO solid source, expanding the scope of the limited examples. This method is compatible with a variety of substitutions on the aniline moiety. The simple reaction conditions include easily available Pd(dppf)Cl2 catalyst, DBU as base in DMF at 120 °C for 3 hours in sealed tube thereby leading to the isolation of 21 compounds with yields ranging from 18 to 82%. We also show that double aminocarbonylation reactions are possible in satisfactory yields regarding both coupling partners. [ABSTRACT FROM AUTHOR]

We describe herein the palladium-catalyzed aminocarbonylation of nitrogen-containing heterocycles with aniline derivatives using molybdenum hexacarbonyl as a CO solid source, expanding the scope of the limited examples. This method is compatible with a variety of substitutions on the aniline moiety. The simple reaction conditions include easily available Pd(dppf)Cl2 catalyst, DBU as base in DMF at 120 °C for 3 hours in sealed tube thereby leading to the isolation of 21 compounds with yields ranging from 18 to 82%. We also show that double aminocarbonylation reactions are possible in satisfactory yields regarding both coupling partners. [ABSTRACT FROM AUTHOR]

Abstract: Described herein is a direct cyclization of simple tertiary aryl amines with iodonium ylides leading to a broad range of N‐heterocycles. Completely different from the known reactivity of iodonium ylides, the finding reported herein is that an iodonium ylide is capable of cleaving a C(sp3)−H bond and accepting two hydrogen atoms of a tertiary aryl amine, thus inducing a novel cyclization process. This transformation can proceed without the assistance of a transition‐metal catalyst and eliminates the need for the premodification of the amine or the use of an additional initiator/oxidant. [ABSTRACT FROM AUTHOR]

We herein report a serendipitously observed acid mediated rearrangement of monoethylene ketal of 2-methyl-2-(3-methylbut-2-en-1-yl)cyclohex-4-ene-1,3-diones to Dihydrobenzopyran and demonstrated the application of this methodology in the construction of core carbon scaffolds of dimethoxyajacareubin, cariphenone-A and crotamadine. [ABSTRACT FROM AUTHOR]

A convenient method for N-arylethylation of aromatic amines and heterocycles under mild reductive conditions was developed using (2-methoxyvinyl)(hetero)arenes as building blocks and triethylsilane/ trifluoroacetic acid as reducing agent. This protocol is compatible with numerous functional groups, and aliphatic amines are inert due to protonation. [ABSTRACT FROM AUTHOR]

A one-pot tandem synthesis of substituted quinolines involving selective catalytic oxidation of primary alcohols to the corresponding aldehydes and their subsequent condensation with arylamines has been developed. Fe(CrO2)2 has been used as a catalyst, and oxidation has been performed with aqueous H2O2. To accelerate the catalytic oxidation of alcohols, photoactivation method has been applied. [ABSTRACT FROM AUTHOR]

The article describes a synthesis of new per- and polyfluorinated oxaziridines along with some reactions of these materials. [ABSTRACT FROM AUTHOR]

Herein, we have studied the micellization of imidazolium-based ionic liquid type gemini surfactant ([C12-4-C12im]Br2) in the absence and presence of aromatic amino acids by conductivity and surface tension measurements at different temperatures (i.e., 298, 308, and 318 K). Various interfacial parameters, that is, Gibbs surface excess (Γmax), minimum head group area at air/water interface (Amin), and thermodynamic parameters, that is, free energy of micellization/adsorption (), the standard entropy of micellization/adsorption (), and the standard enthalpy of micellization/adsorption () were evaluated for all the systems. The standard entropy of adsorption () was found higher than the standard entropy of micellization () for all the systems at all temperatures. The results also showed that the micellization of [C12-4-C12im]Br2depends on the nature of amino acids as well as temperature. TheCMCof [C12-4-C12im]Br2in the absence and presence of amino acids at different temperature decreases with the increase of temperature. [ABSTRACT FROM AUTHOR]