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Xiao-Na Pang, Zhao-Jie Li, Jing-Yu Chen, Li-Juan Gao, Bei-Zhong Han
Standards and regulations related to spirit drinks have been established by different countries and international organizations to ensure the safety and quality of spirits. Here, we introduce the principles of food safety and quality standards for alcoholic beverages and then compare the key indicators used in the distinct standards of the Codex Alimentarius Commission, the European Union, the People's Republic of China, the United States, Canada, and Australia. We also discuss in detail the "maximum level" of the following main contaminants of spirit drinks: methanol, higher alcohols, ethyl carbamate, hydrocyanic acid, heavy metals, mycotoxins, phthalates, and aldehydes...
February 16, 2017: Journal of Food Protection
Chunhui Dai, Julien Genovino, Bruce M Bechle, Matthew S Corbett, Chan Woo Huh, Colin R Rose, Jianmin Sun, Joseph S Warmus, David C Blakemore
A three-component, titanium-mediated synthesis of α-branched N-acylamines from commercial or readily accessible amides, aldehydes, and organometallic reagents is reported. The transformation proceeds under mild reaction conditions and tolerates a variety of functional groups (including nitrile, carbamate, olefin, basic amine, furan, and other sensitive heteroaromatics) to generate a large umbrella of α-branched N-acylamine products in high yields. The operationally practical procedure enables the use of this method in parallel chemical synthesis, a valuable feature that can facilitate the screening of bioactive molecules by medicinal chemists...
February 15, 2017: Organic Letters
Peng Xiong, He-Huan Xu, Hai-Chao Xu
A metal- and reagent-free, electrochemical intramolecular oxidative amination reaction of tri- and tetrasubstituted alkenes has been developed. The electrosynthetic method proceeds through radical cyclization to form the key C-N bond, allowing a variety of hindered tri- and tetrasubstituted olefins to participate in the amination reaction. The result is the efficient synthesis of a host of alkene-bearing cyclic carbamates and ureas and lactams.
February 15, 2017: Journal of the American Chemical Society
Ming Bu, Tingting Cao, Hongxia Li, Mingzhou Guo, Burton B Yang, Chengchu Zeng, Liming Hu
By inspiration of significant anticancer activity of our previously screened natural ergosterol peroxide (1), a series of novel ergosterol peroxide 3-carbamate derivatives were synthesized and characterized. The anti-proliferative activity of synthesized compounds against human hepatocellular carcinoma cells (HepG2, SK-Hep1) and human breast cancer cells (MCF-7, MDA-MB231) were investigated. Compound 3d, 3f and their hydrochloride exhibited significant in vitro anti-proliferative activity against the tested tumor cell lines, with IC50 values ranging from 0...
February 15, 2017: ChemMedChem
Xiaofeng Liu, Qian Zhang, Nandi Zhou, Yaping Tian
Urea in alcoholic beverage is a precursor of ethyl carbamate (EC), which is carcinogenic. Enzymatic elimination of urea has attracted much research interest. Acid urease with good tolerance toward ethanol and acid is ideal enzyme for such applications. In the present work, the structural genes of urease from Providencia rettgeri JN-B815, ureABC were efficiently expressed in E. coli BL21(DE3) in an active form (apourease) exhibiting both urease and urethanase (hydrolyze EC) activities. The specific activities of the purified apourease were comparatively low, which were 2...
February 14, 2017: Molecular Biotechnology
Nicola Gray, Rabiya Zia, Adam King, Vishal C Patel, Julia Wendon, Mark J W McPhail, Muireann Coen, Robert S Plumb, Ian D Wilson, Jeremy K Nicholson
A targeted reversed-phase gradient UPLC-MS/MS assay has been developed for the quantification /monitoring of 66 amino acids and amino-containing compounds in human plasma and serum using precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQTag Ultra). Derivatization of the target amines required minimal sample preparation and resulted in analytes with excellent chromatographic and mass spectrometric detection properties. The resulting method, which requires only 10 μL of sample, provides the reproducible and robust separation of 66 analytes in 7...
February 7, 2017: Analytical Chemistry
Mahboobeh Sharifi, Mohammad Ghadamyari, Khodayar Gholivand, Ali Asghar Ebrahimi Valmoozi, Reza H Sajedi
Insect acetylcholinesterase (AChE) is the principal target for organophosphate (OP) and carbamate (CB) insecticides. In this research, an AChE from third instar larvae of elm left beetle, Xanthogaleruca luteola was purified by affinity chromatography. The enzyme was purified 75.29-fold with a total yield of 8.51%. As shown on denaturing SDS-PAGE, the molecular mass of purified AChE was 70kDa. The enzyme demonstrated maximum activity at pH7 and 35°C. Furthermore, a series of temephos (Tem) derivatives with the general structure of P(O)XP(O) (1-44) were prepared, synthesized and characterized by (31)P, (13)C, (1)H NMR and FT-IR spectral techniques...
March 2017: Pesticide Biochemistry and Physiology
Xiangbo Zhao, Wu Li, Junjie Wang, Dawei Ma
The Hoppe's homoaldol reaction of a cyclo-hexenyl carbamate with an aldehyde followed by an unprecedented BF3·OEt2 mediated intramolecular Mukaiyama-Michael-type reaction affords the tetracyclic core structure of ent-kaurane diterpenoids. The usage of this convergent approach for assembling these natural products is demonstrated by the first asymmetric total syntheses of two highly oxidized ent-kaurane diterpenoids: Lungshengenin D and 1α,6α-diacetoxy-ent-kaura-9(11),16-dien-12,15-dione.
February 14, 2017: Journal of the American Chemical Society
Rebecca Coleman, Sharon W Lemire, William Bragg, Alaine Garrett, Geovannie Ojeda-Torres, Rebekah Wharton, Elizabeth Hamelin, Jerry Thomas, Rudolph C Johnson
Paralytic shellfish toxins (PSTs), including gonyautoxins and saxitoxins, are produced by multiple species of microalgae and dinoflagellates, and are bioaccumulated by shellfish and other animals. Human exposure to PSTs typically occurs through ingestion of recreationally-harvested contaminated shellfish and results in non-specific symptomology. Confirmation of exposure to PSTs has often relied on the measurement of saxitoxin, the most toxic congener; however, gonyautoxins (GTXs), the sulfated carbamate derivatives of saxitoxin, may be present in shellfish at higher concentrations...
February 10, 2017: Biomedical Chromatography: BMC
Peng Zhang, Guocheng Du, Huijun Zou, Guangfa Xie, Jian Chen, Zhongping Shi, Jingwen Zhou
Ubiquitination can significantly affect the endocytosis and degradation of plasma membrane proteins. Here, the ubiquitination of a Saccharomyces cerevisiae urea plasma membrane transporter (Dur3p) was altered. Two potential ubiquitination sites, lysine residues K556 and K571, of Dur3p were predicted and replaced by arginine, and the effects of these mutations on urea utilization and formation under different nitrogen conditions were investigated. Compared with Dur3p, the Dur3pK556R mutant showed a 20.1% decrease in ubiquitination level in yeast nitrogen base medium containing urea and glutamine...
February 10, 2017: Journal of Agricultural and Food Chemistry
Alessio De Simone, Debora Russo, Gian Filippo Ruda, Alessandra Micoli, Mariarosaria Ferraro, Rita Maria Concetta Di Martino, Giuliana Ottonello, Maria Summa, Andrea Armirotti, Tiziano Bandiera, Andrea Cavalli, Giovanni Bottegoni
We recently reported molecules designed according to the multi-target-directed ligand paradigm to exert combined activity at human fatty acid amide hydrolase (FAAH) and dopamine receptor subtype D3 (D3R). Both targets are relevant for tackling several types of addiction (most notably nicotine addiction) and other compulsive behaviors. Here, we report an SAR exploration of a series of biphenyl-N-[4-[4-(2,3-substituted-phenyl)piperazine-1-yl]alkyl]carbamates, a novel class of molecules that had shown promising activities at the FAAH - D3R target combination in preliminary studies...
February 9, 2017: Journal of Medicinal Chemistry
Soona Park, Jeong Tae Lee, Jungwon Kim
The photocatalytic oxidation of urea on TiO2 in water was compared with that in urine. Despite the presence of other organic compounds in urine, the oxidation efficiency of urea on TiO2 in urine was higher than that in water. This enhanced oxidation of urea in urine is ascribed to the higher production of (•)OH (primary oxidant for urea degradation) by the adsorption of PO4(3-) (one constituent of urine) on the TiO2 surface. Among the various anions in urine, only PO4(3-) was adsorbed on the surface of TiO2...
February 4, 2017: Environmental Science and Pollution Research International
Carlos Calderón, Michael Lämmerhofer
Chiral short chain aliphatic hydrocarboxylic acids (HCAs) are common compounds being part of different biological processes. In order to control and understand these processes is of pivotal importance to determine the identity of the involved enantiomer or their enantiomeric ratio. In this study the capacity of quinine- and quinidine-derived chiral stationary phases to perform the enantioseparation of eight chiral HCAs (tartaric acid, isocitric acid, malic acid, glyceric acid, 2-hydroxyglutaric acid, 2-hydroxybutyric acid, lactic acid and 3-hydroxybutyric acid) was evaluated...
January 24, 2017: Journal of Chromatography. A
Rajiv T Sawant, Marc Y Stevens, Luke R Odell
A novel acetic acid-promoted metal-free cascade N-acyliminium ion/aza-Prins cyclization of o-formyl carbamates and homoallylamines is reported. This one-pot protocol provides efficient and rapid access to masked cis-hydroxyhexahydropyrido[1,2-c]quinazolin-6-ones with concomitant generation of two stereogenic centers, four C-C/C-O/C-N bonds and two new rings in good yield and excellent diastereoselectivity.
February 9, 2017: Chemical Communications: Chem Comm
Jean-François Lohier, Thomas Glachet, Hamid Marzag, Annie-Claude Gaumont, Vincent Reboul
We report a new procedure for the preparation of NH-sulfoximines from sulfides using PIDA as an oxidant and ammonium carbamate as the ammonia source. Excellent yields were obtained with a wide range of sulfides. The formation of acetoxy- and methoxy-λ(6)-sulfanenitrile as intermediates was proposed, both of which were converted to the NH-sulfoximine by the action of the solvent. The structure of these intermediates was confirmed by (1)H, (13)C and (15)N NMR and HRMS analysis.
January 30, 2017: Chemical Communications: Chem Comm
Peter E Chen, Nicholas C Anderson, Zachariah M Norman, Jonathan S Owen
To completely displace the carboxylate surface ligands from cadmium selenide nanocrystals, oleic acid impurities are first removed using dimethylcadmium or diethylzinc. In addition to metal carboxylate and methane coproducts, reactions with CdMe2 produce surface bound methyl groups (δ = 0.4 ppm, 0.04-0.22 nm(-2)) that photolytically dissociate to methyl radicals and n-doped nanocrystals. Without oleic acid impurities, cadmium carboxylate can be completely displaced from the surface using n-alkylamines (NH2R', R' = n-butyl, n-hexyl, n-octyl) (≤0...
February 16, 2017: Journal of the American Chemical Society
Qiao Zhang, Hao-Yu Yuan, Norihisa Fukaya, Hiroyuki Yasuda, Jun-Chul Choi
Several zinc salts were employed as catalysts for the synthesis of carbamates directly from aromatic amines, CO2, and silicate esters. Zn(OAc)2 offered the best performance among the salts tested. The addition of an N-donor ligand such as 1,10-phenanthroline increased the yield. The best catalytic performance of Zn(OAc)2 can be explained by carboxylate-assisted proton activation. The interaction between the substrate and the catalyst can be observed by chemical shifts from 1H and 15N NMR. Isocyanate was a key intermediate which was generated from amine and CO2...
January 26, 2017: ChemSusChem
Weigao Hu, Jiawei Li, Yanli Xu, Jianxiao Li, Wanqing Wu, Haiyang Liu, Huanfeng Jiang
A redox-neutral palladium-catalyzed N-O/C(sp(3))-H functionalization of aryl oximes with isocyanides has been developed. Various pyrrole derivatives were prepared in good to excellent yields through oxime carbamate as a key intermediate and internal oxidant in this process. Furthermore, this transformation also features readily available starting materials, good functional group tolerance, and excellent regioselectivity.
January 25, 2017: Organic Letters
Lin Zhang, Pin Xiao, Xiaoxue Guan, Zhouliang Huang, Jingping Zhang, Xihe Bi
The radical coupling of isocyanides and alcohols/phenols promoted by silver in the presence of water is reported for the first time, which led to the formation of diverse carbamates. In contrast to the well-known 1,1-addition to form imidoyl radicals, a novel reaction mechanism, involving sequential hydration of isocyanides and coupling with alkoxyl/phenoxyl radicals, is disclosed by combining experimental and theoretical studies.
January 25, 2017: Organic & Biomolecular Chemistry
Youbin Peng, Juan Liu, Chaorong Qi, Gaoqing Yuan, Jiawei Li, Huanfeng Jiang
The first nBu4NI-catalyzed oxidative cross-coupling reaction of carbon dioxide, amines and arylketones has been successfully developed by using TBHP as the oxidant, providing an efficient, atom-economical and metal-free strategy for the synthesis of a range of O-β-oxoalkyl carbamates.
January 23, 2017: Chemical Communications: Chem Comm
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