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Yael Abreu-Villaça, Edward D Levin
Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids...
November 28, 2016: Environment International
Ángel Gabriel Díaz-Sánchez, Emilio Alvarez-Parrilla, Alejandro Martínez-Martínez, Luis Aguirre-Reyes, Jesica Aline Orozpe-Olvera, Miguel Armando Ramos-Soto, José Alberto Núñez-Gastélum, Bonifacio Alvarado-Tenorio, Laura Alejandra de la Rosa
Urease is a nickel-dependent amidohydrolase that catalyses the decomposition of urea into carbamate and ammonia, a reaction that constitutes an important source of nitrogen for bacteria, fungi and plants. It is recognized as a potential antimicrobial target with an impact on medicine, agriculture, and the environment. The list of possible urease inhibitors is continuously increasing, with a special interest in those that interact with and block the flexible active site flap. We show that disulfiram inhibits urease in Citrullus vulgaris (CVU), following a non-competitive mechanism, and may be one of this kind of inhibitors...
November 26, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Nichola J Hawkins, Bart A Fraaije
When a new fungicide class is introduced, it is useful to anticipate the resistance risk in advance, attempting to predict both risk level and potential mechanisms. One tool for the prediction of resistance risk is laboratory selection for resistance, with the mutational supply increased through UV or chemical mutagenesis. This enables resistance to emerge more rapidly than in the field, but may produce mutations that would not emerge under field conditions. The methyl benzimidazole carbamates (MBCs) were the first systemic single-site agricultural fungicides, and the first fungicides affected by rapid evolution of target-site resistance...
2016: Frontiers in Microbiology
Luca Mazzei, Michele Cianci, Francesco Musiani, Gábor Lente, Marta Palombo, Stefano Ciurli
Urease is a Ni(II)-containing enzyme that catalyzes the hydrolysis of urea to yield ammonia and carbamate at a rate 10(15) times higher than the uncatalyzed reaction. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Therefore, efficient urease inhibitors are actively sought. In this study, we describe a molecular characterization of the interaction between urease from Sporosarcina pasteurii (SPU) and Canavalia ensiformis (jack bean, JBU) with catechol, a model polyphenol...
November 9, 2016: Journal of Inorganic Biochemistry
Norman L Carreck
Bees and agrochemicals have a long history. For example the first volume of IBRA's journal Bee World in 1919 contains mention of poisoning of bees by spraying an orchard with lead arsenate. Being insects, it is self-evident that the use of insecticides to control crop pests poses a risk to bees. Bee poisoning incidents became a very serious problem in the 1960s and 1970s with spraying of, in particular, oilseed rape with organophosphorus compounds. The introduction of carbamates and then especially synthetic pyrethroids reduced these problems...
November 25, 2016: Pest Management Science
Dongxing Chen, Jinyu Shi, Jing Liu, Xueying Zhang, Xiaoying Deng, Yanyan Yang, Shuang Cui, Qihua Zhu, Guoqing Gong, Yungen Xu
Ten derivatives of 4-((1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-1-yl)methyl)benzimida-mide (I-1∼I-2, II-1∼II-8) were designed, synthesized and evaluated for their inhibitory effect on human thrombin. Compound II-7 (IC50=82.8nM), which showed the strongest thrombin inhibitory activity among the tested compounds, was chosen as the lead compound, and ten carbamate derivatives (II-9a∼II-13a, II-9b∼II-12b, II-14) were prepared and evaluated for their anticoagulant activity. The results indicate that most of the tested compounds exhibit a certain degree of inhibitory effect on thrombin-induced platelet aggregation, among which compounds II-11a (IC50=8...
November 9, 2016: Bioorganic & Medicinal Chemistry
Josefina Priotti, Ana V Codina, Darío Leonardi, María D Vasconi, Lucila I Hinrichsen, María C Lamas
The oral route has notable advantages to administering dosage forms. One of the most important questions to solve is the poor solubility of most drugs which produces low bioavailability and delivery problems, a major challenge for the pharmaceutical industry. Albendazole is a benzimidazole carbamate extensively used in oral chemotherapy against intestinal parasites, due to its extended spectrum activity and low cost. Nevertheless, the main disadvantage is the poor bioavailability due to its very low solubility in water...
November 23, 2016: AAPS PharmSciTech
Donglu Zhang, Thomas H Pillow, Yong Ma, Josefa Dela Cruz-Chuh, Katherine R Kozak, Jack D Sadowsky, Gail D Lewis Phillips, Jun Guo, Martine Darwish, Peter Fan, Jingtian Chen, Changrong He, Tao Wang, Hui Yao, Zijin Xu, Jinhua Chen, John Wai, Zhonghua Pei, Cornelis E C A Hop, S Cyrus Khojasteh, Peter S Dragovich
Disulfide bonds could be valuable linkers for a variety of therapeutic applications requiring tunable cleavage between two parts of a molecule (e.g., antibody-drug conjugates). The in vitro linker immolation of β-mercaptoethyl-carbamate disulfides and DNA alkylation properties of associated payloads were investigated to understand the determinant of cell killing potency of anti-CD22 linked pyrrolobenzodiazepine (PBD-dimer) conjugates. Efficient immolation and release of a PBD-dimer with strong DNA alkylation properties were observed following disulfide cleavage of methyl- and cyclobutyl-substituted disulfide linkers...
November 10, 2016: ACS Medicinal Chemistry Letters
L Nathan Tumey, Carolyn A Leverett, Beth Vetelino, Fengping Li, Brian Rago, Xiaogang Han, Frank Loganzo, Sylvia Musto, Guoyun Bai, Sai Chetan K Sukuru, Edmund I Graziani, Sujiet Puthenveetil, Jeffrey Casavant, Anokha Ratnayake, Kimberly Marquette, Sarah Hudson, Venkata Ramana Doppalapudi, Joseph Stock, Lioudmila Tchistiakova, Andrew J Bessire, Tracey Clark, Judy Lucas, Christine Hosselet, Christopher J O'Donnell, Chakrapani Subramanyam
As part of our efforts to develop new classes of tubulin inhibitor payloads for antibody-drug conjugate (ADC) programs, we developed a tubulysin ADC that demonstrated excellent in vitro activity but suffered from rapid metabolism of a critical acetate ester. A two-pronged strategy was employed to address this metabolism. First, the hydrolytically labile ester was replaced by a carbamate functional group resulting in a more stable ADC that retained potency in cellular assays. Second, site-specific conjugation was employed in order to design ADCs with reduced metabolic liabilities...
November 10, 2016: ACS Medicinal Chemistry Letters
Themba Mzilahowa, Martin Chiumia, Rex B Mbewe, Veronica T Uzalili, Madalitso Luka-Banda, Anna Kutengule, Don P Mathanga, Doreen Ali, John Chiphwanya, John Zoya, Shadreck Mulenga, Wilfred Dodoli, Jennifer Bergeson-Lockwood, Peter Troell, Jessica Oyugi, Kim Lindblade, John E Gimnig
BACKGROUND: Susceptibility of principal Anopheles malaria vectors to common insecticides was monitored over a 5-year period across Malawi to inform and guide the national malaria control programme. METHODS: Adult blood-fed Anopheles spp. and larvae were collected from multiple sites in sixteen districts across the country between 2011 and 2015. First generation (F1) progeny aged 2-5 days old were tested for susceptibility, using standard WHO procedures, against pyrethroids (permethrin and deltamethrin), carbamates (bendiocarb and propoxur), organophosphates (malathion and pirimiphos-methyl) and an organochlorine (DDT)...
November 22, 2016: Malaria Journal
Rousseau J Djouaka, Seun M Atoyebi, Genevieve M Tchigossou, Jacob M Riveron, Helen Irving, Romaric Akoton, Michael O Kusimo, Adekunle A Bakare, Charles S Wondji
BACKGROUND: Knowing the extent and spread of insecticide resistance in malaria vectors is vital to successfully manage insecticide resistance in Africa. This information in the main malaria vector, Anopheles funestus sensu stricto, is completely lacking in the most populous country in Africa, Nigeria. This study reports the insecticide susceptibility status and the molecular basis of resistance of An. funestus as well as its involvement in malaria transmission in Akaka-Remo, a farm settlement village in southwest Nigeria...
November 22, 2016: Malaria Journal
Leanna R Staben, Stefan G Koenig, Sophie M Lehar, Richard Vandlen, Donglu Zhang, Josefa Chuh, Shang-Fan Yu, Carl Ng, Jun Guo, Yanzhou Liu, Aimee Fourie-O'Donohue, MaryAnn Go, Xin Linghu, Nathaniel L Segraves, Tao Wang, Jinhua Chen, BinQing Wei, Gail D Lewis Phillips, Keyang Xu, Katherine R Kozak, Sanjeev Mariathasan, John A Flygare, Thomas H Pillow
The reversible attachment of a small-molecule drug to a carrier for targeted delivery can improve pharmacokinetics and the therapeutic index. Previous studies have reported the delivery of molecules that contain primary and secondary amines via an amide or carbamate bond; however, the ability to employ tertiary-amine-containing bioactive molecules has been elusive. Here we describe a bioreversible linkage based on a quaternary ammonium that can be used to connect a broad array of tertiary and heteroaryl amines to a carrier protein...
December 2016: Nature Chemistry
Austin Baranek, Han Byul Song, Mathew McBride, Patricia Finnegan, Christopher N Bowman
Bulk photopolymerization of a library of synthesized multifunctional azides and alkynes was carried out toward developing structure-property relationships for CuAAC-based polymer networks. Multifunctional azides and alkynes were formulated with a copper catalyst and a photoinitiator, cured, and analyzed for their mechanical properties. Material properties such as the glass transition temperatures (Tg) show a strong dependence on monomer structure with Tg values ranging from 41 to 90 °C for the series of CuAAC monomers synthesized in this study...
February 23, 2016: Macromolecules
Sheng Tang, Jian-De Liu, Qin Bin, Ke-Qin Fu, Xiao-Chen Wang, Ying-Bin Luo, Shao-Hua Huang, Zheng-Wu Bai
In order to comprehensively understand the influence of coordination of the substituent at 2-position with those at 3- and 6-positions on the properties of chitosan derivatives, a series of chitosan 3,6-bis(arylcarbamate)-2-(amide)s (CACAs) and the related chiral stationary phases (CSPs) were prepared and reported in the present study. Specifically, chitosan was N-acylated with carboxylic acid anhydrides, and then further derivatized with various aryl isocyanates to afford CACAs, from which a class of coated-type CSPs were prepared...
December 9, 2016: Journal of Chromatography. A
Juho Antti Sirviö, Juha Heiskanen
This study presents the use of a reactive deep eutectic solvent (DES) for the chemical modification of wood cellulose fibers. DES based on dimethylurea and ZnCl2 was used to synthetize cellulose methyl carbamate (CMeC). This synthesis was performed at an elevated temperature under solvent-free conditions. Chemical characterization based on FTIR and NMR indicates that methyl carbamate was successfully introduced to cellulose, and a degree of substitution (DS) of 0.17 was obtained after 3h of reaction at 150 °C...
November 15, 2016: ChemSusChem
Katja Knauer, Nadzeya Homazava, Marion Junghans, Inge Werner
Environmental risk assessment is an essential part of the authorization and approval process for marketing of pesticides. To determine the risk of a substance or formulation for aquatic communities, exposure concentrations are calculated and compared to ecotoxicological data obtained from standardized OECD laboratory studies and, if available, from field studies. Predicted environmental concentrations (PEC) in surface waters are derived using e.g. the European FOCUS or the German Exposit models, which distinguish between exposure to dissolved and particle-associated pesticide concentrations, since the dissolved concentration is thought to be the best predictor of bioavailability and toxicity...
November 15, 2016: Integrated Environmental Assessment and Management
Ahmed M Hamed, David Moreno-González, Laura Gámiz-Gracia, Ana M García-Campaña
A simple and efficient method for the determination of 28 carbamates in high-fat cheeses is proposed. The methodology is based on a modified quick, easy, cheap, effective, rugged, and safe procedure as sample treatment using a new sorbent (Z-Sep(+) ) followed by ultra high performance liquid chromatography with tandem mass spectrometry determination. The method has been validated in different kinds of cheese (Gorgonzola, Roquefort and Camembert), achieving recoveries of 70-115%, relative standard deviations lower than 13% and limits of quantification lower than 5...
November 18, 2016: Journal of Separation Science
Xi Liu, Mei-Yan Wang, Si-Yuan Wang, Qi Wang, Liang-Nian He
Incorporation of CO2 into heterocycle compounds i.e. 2-oxazolidinones under mild conditions, especially at atmospheric pressure still remains challenging. The mononuclear zinc(II) complex viz. ZnCl2(TBD)2 in this study was for the first time demonstrated as a robust catalyst for the carboxylative cyclization of propargylic amines with CO2 to exclusively afford various 2-oxazolidinones in excellent yields. Notably, the zinc(II) catalytic species is readily in situ generated from zinc dichloride and 1,5,7-triazabicyclo[4...
November 8, 2016: ChemSusChem
Stephanie R McCabe, Peter Wipf
The first enantioselective total synthesis of (-)-cycloclavine was accomplished in 8 steps and 7.1 % overall yield. Key features include the first catalytic asymmetric cyclopropanation of allene, mediated by the dirhodium catalyst Rh2 (S-TBPTTL)4 , and the enone 1,2-addition of a new TEMPO carbamate methyl carbanion. An intramolecular strain-promoted Diels-Alder methylenecyclopropane (IMDAMC) reaction provided a pivotal tricyclic enone intermediate with more than 99 % ee after crystallization. The synthesis of (-)-1 was completed by a late-stage intramolecular Diels-Alder furan (IMDAF) cycloaddition to install the indole...
November 18, 2016: Angewandte Chemie
Madhuri Vangala, Ganesh P Shinde
The amidine bases DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and DBN (1,5-diazabicyclo[4.3.0]non-5-ene) display nucleophilic behaviour towards highly electrophilic p-nitrophenyl carbonate derivatives with ring opening of the bicyclic ring to form corresponding substituted ε-caprolactam and γ-lactam derived carbamates. This simple method presents a unified strategy to synthesize structurally diverse ε-caprolactam and γ-lactam compounds with a large substrate scope.
2016: Beilstein Journal of Organic Chemistry
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