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https://www.readbyqxmd.com/read/28932459/crystal-structure-determination-as-part-of-an-ongoing-undergraduate-organic-laboratory-project-5-e-styr-yl-1-3-4-oxa-thia-zol-2-one
#1
Trevor R Nason, Melbourne J Schriver, Arthur D Hendsbee, Jason D Masuda
The title compound, C10H7NO2S, provides the first structure of an α-alkenyl oxa-thia-zolone ring. The phenyl ring and the oxa-thia-zolone groups make dihedral angles of 0.3 (3) and -2.8 (3)°, respectively, with the plane of the central alkene group; the dihedral angle between the rings is 2.68 (8)°. A careful consideration of bond lengths provides insight into the electronic structure and reactivity of the title compound. In the crystal, extended π-stacking is observed parallel to the a-axis direction, consisting of cofacial head-to-tail dimeric units [centroid-centroid distance of 3...
September 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28932440/ethyl-2-4-meth-oxy-phen-yl-6-oxa-3-aza-bicyclo-3-1-0-hexane-3-carboxyl-ate-crystal-structure-and-hirshfeld-analysis
#2
Julio Zukerman-Schpector, Fabricia H Sugiyama, Ariel L L Garcia, Carlos Roque D Correia, Mukesh M Jotani, Edward R T Tiekink
The title compound, C14H17NO4, features an epoxide-O atom fused to a pyrrolidyl ring, the latter having an envelope conformation with the N atom being the flap. The 4-meth-oxy-phenyl group is orthogonal to [dihedral angle = 85.02 (6)°] and lies to the opposite side of the five-membered ring to the epoxide O atom, while the N-bound ethyl ester group (r.m.s. deviation of the five fitted atoms = 0.0187 Å) is twisted with respect to the ring [dihedral angle = 17.23 (9)°]. The most prominent inter-actions in the crystal are of the type methine-C-H⋯O(carbon-yl) and these lead to the formation of linear supra-molecular chains along the c axis; weak benzene-C-H⋯O(epoxide) and methine-C-H⋯O(meth-oxy) inter-actions connect these into a three-dimensional architecture...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28929963/-comparison-of-phenotypic-methods-and-polymerase-chain-reaction-for-the-detection-of-carbapenemase-production-in-clinical-klebsiella-pneumoniae-isolates
#3
Yamaç Tekintaş, Feriha Çilli, Bayrı Eraç, Melike Yaşar, Sabire Şöhret Aydemir, Mine Hoşgör Limoncu
Being a member of the Enterobacteriaceae family, Klebsiella pneumoniae is an opportunistic pathogen that inhabits normal human microbiota and causes predominantly hospital-acquired infections. The emergence of K.pneumoniae isolates which are resistant particularly to the carbapenem group of antibiotics has led to an increase in hospitalization period, mortality and morbidity. Although different rates of resistance are observed between countries, regions and even healthcare facilities, there has been a rapid increase in the prevalence of carbapenem-resistant strains in the last 10 years...
July 2017: Mikrobiyoloji Bülteni
https://www.readbyqxmd.com/read/28893449/successful-control-of-2-simultaneous-outbreaks-of-oxa-48-carbapenemase-producing-enterobacteriaceae-and-multidrug-resistant-acinetobacter-baumannii-in-an-intensive-care-unit
#4
A Robustillo-Rodela, V Pérez-Blanco, M A Espinel Ruiz, G Ruiz Carrascoso, J C Figueira Iglesias, D Abad Martín
BACKGROUND: This report describes a double outbreak of OXA-48-producing Enterobacteriaceae (OXA-48-PE) and multidrug-resistant Acinetobacter baumannii (MRAB) in an intensive care unit (ICU) and the effectiveness of measures implemented, including decontamination with vaporized hydrogen peroxide (VHP). METHODS: Affected patients were isolated in a confined area and cared for by dedicated personnel. Four percent chlorhexidine soap was used for patient daily hygiene...
September 8, 2017: American Journal of Infection Control
https://www.readbyqxmd.com/read/28891949/isaria-fumosorosea-kch-j2-entomopathogenic-strain-as-an-effective-biocatalyst-for-steroid-compound-transformations
#5
Ewa Kozłowska, Monika Dymarska, Edyta Kostrzewa-Susłow, Tomasz Janeczko
The catalytic activity of enzymes produced by an entomopathogenic filamentous fungus (Isaria fumosorosea KCh J2) towards selected steroid compounds (androstenedione, adrenosterone, progesterone, 17α-methyltestosterone and dehydroepiandrosterone) was investigated. All tested substrates were efficiently transformed. The structure of the substrate has a crucial impact on regio- and stereoselectivity of hydroxylation since it affects binding to the active site of the enzyme. Androstenedione was hydroxylated in the 7α-position to give a key intermediate in the synthesis of the diuretic-7α-hydroxyandrost-4-ene-3,17-dione with 82% conversion...
September 9, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28888401/detection-of-carbapenemases-and-other-mechanisms-of-enzymatic-resistance-to-%C3%AE-lactams-in-enterobacteriaceae-with-diminished-susceptibility-to-carbapenems-in-a-tertiary-care-hospital
#6
Marta María Gómara-Lomero, Ana Isabel López-Calleja, Berta María Pilar Vela Iglesia, Isabel Ferrer Cerón, Antonio Rezusta López, María José Revillo Pinilla
INTRODUCTION: Our objective was to characterize the enzymatic β-lactam resistance in clinical Enterobacteriaceae isolates with diminished susceptibility to carbapenems from 2013 to 2014 at Hospital Universitario Miguel Servet. MATERIAL/METHODS: A total of 63 clinical isolates were analyzed for the presence of carbapenemases (KPC, OXA-48 and MBL), ESBLs and AmpC enzymes by combined disk methods and PCR detection of carbapenemase-encoding and beta-lactamase-encoding genes...
September 6, 2017: Enfermedades Infecciosas y Microbiología Clínica
https://www.readbyqxmd.com/read/28887772/fortuitous-detection-of-cmy-2-and-dha-1-from-esbl-producing-escherichia-coli-in-senegal
#7
S Lo, F Robin, A Ba-Diallo, O F Diallo, M L Dia, R Beyrouthy, A Gaye-Diallo, A I Sow, R Bonnet
Cephalosporinases, which are naturally present in some enterobacterial species, can be mobilized by transposons, migrate to plasmids, and spread into other species such as Escherichia coli. The aim of this study was to characterize genes responsible for the production of extended-spectrum β-lactamases (ESBL) in E. coli isolates from urinary origin isolated in two hospitals in Senegal. Thus, a fortuitous discovery of plasmidic cephalosporinase in two isolates was noted. One of the isolates produced dha-1 associated with ESBL CTX-M-14, the other produced cmy-2, ESBL CTXM-15, tem-1 penicillinase, and oxa-1...
September 8, 2017: Bulletin de la Société de Pathologie Exotique
https://www.readbyqxmd.com/read/28884964/anion-%C3%AF-catalysis-of-diels-alder-reactions
#8
Le Liu, Yoann Cotelle, Anna-Bea Bornhof, Céline Besnard, Naomi Sakai, Stefan Matile
Among concerted cycloadditions, the Diels-Alder reaction is the grand old classic, which is usually achieved with acid catalysis. In this report, hydroxypyrones, oxa-, and thiazolones are explored because they provide access to anionic dienes. Their [4+2] cycloaddition with cyclic and acyclic dienophiles, such as maleimides and fumarates, affords bicyclic products with four new stereogenic centers. Bifunctional anion-π catalysts composed of amine bases next to the π surface of naphthalenediimides (NDIs) are shown to selectively stabilize the "open", fully accessible anionic exo transition state on the π-acidic aromatic surface...
September 8, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28882642/risk-factors-for-acquisition-of-producing-oxa-48-klebsiella-pneumonia-among-contact-patients-a-multicenter-study
#9
D Hilliquin, R Le Guern, V Thepot Seegers, C Neulier, A Lomont, V Marie, C Legeay, J Merrer, D Lepelletier, A M Rogues, B Grandbastien, J C Lucet, J R Zahar
Cohorting carbapenemase-producing Enterobacteriaceae (CPE) carriers during hospitalisation limits the in hospital spreading. Our objective was to identify risk factors for CPE acquisition among contacts of an index patient in non-cohorted populations. A multicentre retrospective matched case-control study was conducted in five hospitals. Each contact patient (case) who acquired Klebsiella pneumoniae OXA-48 from an index patient was compared to three contact (controls) with the same index patients matched with hospitalization in the same unit and similar exposure-times...
September 4, 2017: Journal of Hospital Infection
https://www.readbyqxmd.com/read/28876471/taxadiene-5%C3%AE-ol-is-a-minor-product-of-cyp725a4-when-expressed-in-escherichia-coli
#10
Laxmi Sagwan-Barkdoll, Aldwin M Anterola
CYP725A4 is a P450 enzyme from Taxus cuspidata that catalyzes the formation of taxadiene-5α-ol (T5α-ol) from taxadiene in paclitaxel biosynthesis. Past attempts expressing CYP725A4 in heterologous hosts reported the formation of 5(12)-oxa-3(11)-cyclotaxane (OCT) and/or 5(11)-oxa-3(11)-cyclotaxane (iso-OCT) instead of, or in addition to, T5α-ol. Here we report that T5α-ol is produced as a minor product by Escherichia coli expressing both taxadiene synthase (TS) and CYP725A4. The major products were OCT and iso-OCT, while trace amounts of unidentified monooxygenated taxanes were also detected by gas chromatography-mass spectrometry...
September 6, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28876082/co-production-of-ndm-1-and-oxa-232-by-st16-klebsiella-pneumoniae-italy-2016
#11
Manuela Avolio, Carla Vignaroli, Massimo Crapis, Alessandro Camporese
Carbapenem-resistant Klebsiella pneumoniae strains, New Delhi metallo-β-lactamase-1 producers, are still rare in Italy, being endemic in Southeast Asiatic region. In October 2016, a multidrug-resistant K. pneumoniae was isolated from blood and urine of an Italian long-hospitalized patient with urosepsis without travel history abroad. To the best of our knowledge, this is the first report of bacteremia caused by an ST16 K. pneuomoniae New Delhi metallo-β-lactamase-1 and OXA-232 co-producing carbapenemase, in Italy...
September 6, 2017: Future Microbiology
https://www.readbyqxmd.com/read/28874377/high-level-resistance-to-colistin-mediated-by-various-mutations-in-the-crrb-gene-among-carbapenemase-producing-klebsiella-pneumoniae
#12
Aurélie Jayol, Patrice Nordmann, Adrian Brink, Maria-Virginia Villegas, Véronique Dubois, Laurent Poirel
Mutations in the crrAB genes encoding a two-component regulator involved in modifications of the lipopolysaccharide were searched for among a collection of colistin-resistant Klebsiella pneumoniae isolates. Four isolates respectively producing carbapenemases NDM-1, OXA-181, or KPC-2 showed mutated CrrB proteins compared to wild-type strains. Complementation assays with a wild-type CrrB protein restored the susceptibility to colistin in all cases, confirming the involvement of the identified substitutions in the resistance phenotype...
September 5, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28873732/unprecedented-antioxidative-and-anti-inflammatory-aryl-polyketides-from-the-brown-seaweed-sargassum-wightii
#13
Anusree Maneesh, Kajal Chakraborty
Previously undescribed aryl polyketide lactones, 4-(8-ethyl-tetrahydro-7-oxo-2H-pyran-5-yl)-propyl-4'-methylbenzoate (compound 1) and methyl-2-(12-oxo-7-phenyl-8-vinyl-1-oxa-4,9-cyclododecadien-3-yl)-acetate (compound 2) were purified from ethyl acetate-methanol fraction of the brown seaweed Sargassum wightii. The structures were proposed based on their NMR and mass spectrometric data. The antioxidative activities of the lactones were significantly greater (P<0.05) (IC50 1,1-diphenyl-2-picrylhydrazyl radical scavenging 0...
October 2017: Food Research International
https://www.readbyqxmd.com/read/28872863/metalation-and-selective-oxidation-of-diphenyl-23-oxa-thia-and-selena-21-carbaporphyrins
#14
Timothy D Lash, Gregory M Ferrence
The availability of diphenyl-23-oxa-, -thia-, and -selena-21-carbaporphyrins has enabled the reactivity of these systems to be investigated and contrasted. All three heterocarbaporphyrins reacted with palladium(II) acetate in refluxing chloroform-acetonitrile to give organometallic palladium(II) derivatives in good yields. These structures are stable and give UV-vis spectra that show increasing broadening and bathochromic shifts as the size of the heteroatom increases. Nickel(II) acetate in refluxing N,N-dimethylformamide reacted with the oxa- and thiacarbaporphyrins under nitrogen to give the corresponding nickel(II) complexes, but the selenacarbaporphyrin did not metalate under these conditions...
September 5, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28870269/failure-to-communicate-transmission-of-extensively-drug-resistant-bla-oxa-237-containing-acinetobacter-baumannii-multiple-facilities-in-oregon-2012-2014
#15
Genevieve L Buser, P Maureen Cassidy, Margaret C Cunningham, Susan Rudin, Andrea M Hujer, Robert Vega, Jon P Furuno, Steven H Marshall, Paul G Higgins, Michael R Jacobs, Meredith S Wright, Mark D Adams, Robert A Bonomo, Christopher D Pfeiffer, Zintars G Beldavs
OBJECTIVE To determine the scope, source, and mode of transmission of a multifacility outbreak of extensively drug-resistant (XDR) Acinetobacter baumannii. DESIGN Outbreak investigation. SETTING AND PARTICIPANTS Residents and patients in skilled nursing facilities, long-term acute-care hospital, and acute-care hospitals. METHODS A case was defined as the incident isolate from clinical or surveillance cultures of XDR Acinetobacter baumannii resistant to imipenem or meropenem and nonsusceptible to all but 1 or 2 antibiotic classes in a patient in an Oregon healthcare facility during January 2012-December 2014...
September 5, 2017: Infection Control and Hospital Epidemiology
https://www.readbyqxmd.com/read/28870091/high-prevalence-of-oxa-type-carbapenemases-among-acinetobacter-baumannii-strains-in-a-teaching-hospital-of-tehran
#16
Mandana Zafari, Mohamad Mehdi Feizabadi, Sirous Jafari, Alireza Abdollahi, Azar Sabokbar
Nosocomial infection caused by carbapenem-resistant Acinetobacter baumannii (CRAB) has created a public health concern all around the world. In this study, 100 isolates of CRAB from hospitalized patients during 2015-2016 at Imam Khomeini Hospital were investigated to determine the rates of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains using Kirby-Bauer disk diffusion method. The minimum inhibitory concentrations (MICs) of six antibiotics were determined by broth microdilution method...
September 5, 2017: Acta Microbiologica et Immunologica Hungarica
https://www.readbyqxmd.com/read/28864149/anticancer-potential-of-aminomethylidene-diazinanes-i-synthesis-of-arylaminomethylidene-of-diazinetriones-and-its-cytotoxic-effects-tested-in-glioblastoma-cells
#17
Nichole A Pianovich, Mathew Dean, Adam Lassak, Krzysztof Reiss, Branko S Jursic
Diazinane and aryl moieties with vinylamine linkers were synthesized to investigate the importance of their structural variations as potential anti-glioblastoma agents. Structural variations incorporated on to the diazinane moiety included oxa and thio derivatives, each with a variety of nitrogen-bound substituents. The size and shape of the aromatic moiety was varied, with the final variation introducing two carbonyl groups, yielding a substituted anthraquinone. Readily available diazinanes and aryl amines were used asan advantageous foundation...
August 12, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28862848/enantioselective-aldol-reactions-in-water-by-a-proline-derived-cryptand-and-fixation-of-co2-by-its-exocyclic-co-ii-complex
#18
Dinesh De, Aditya Bhattacharyya, Parimal K Bharadwaj
The secondary amine donors present in the bridges of a laterally nonsymmetric oxa-aza cryptand have been derivatized with l-proline to obtain the chiral cryptand L. The cryptand L efficiently catalyzed aldol reactions in water with up to 75% ee. On reacting with Co(II) perchlorate in the presence of KSCN, L readily formed the trinuclear complex {[Co3(L)2(NCS)6]·(15CH3CN)(5acetone)(6H2O)} (1). The complex 1 in combination with the cocatalyst tetrabutylammonium bromide (TBAB) formed an efficient catalytic system in the synthesis of cyclic carbonates from CO2 and epoxides at room temperature and atmospheric pressure...
September 1, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28862460/electrophilic-cyclization-and-intermolecular-acetalation-of-2-4-hydroxybut-1-yn-1-yl-benzaldehydes-synthesis-of-diiodinated-diepoxydibenzo-c-k-1-9-dioxacyclohexadecines
#19
Jia Wang, Hai-Tao Zhu, Si Chen, Cheng Luan, Yu Xia, Yi Shen, Ying-Xiu Li, Yingxi Hua, Yong-Min Liang
An expedient strategy for the preparation of diiodinated diepoxydibenzo[c,k][1,9]dioxacyclohexadecines from readily available 2-(4-hydroxybut-1-yn-1-yl)benzaldehydes through electrophile-triggered tandem cyclization/intermolecular acetalation sequence has been presented. The electrophilic macrocyclization can be performed under mild conditions and up to gram quantities. Moreover, palladium-catalyzed coupling and reduction reactions of the resulting iodides could efficiently afford oxa-macrocycles.
September 1, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28859446/oxa-427-a-new-plasmid-borne-carbapenem-hydrolysing-class-d-%C3%AE-lactamase-in-enterobacteriaceae
#20
Pierre Bogaerts, Thierry Naas, Veroniek Saegeman, Remy A Bonnin, Annette Schuermans, Stéphanie Evrard, Warda Bouchahrouf, Thomas Jove, Didier Tande, Xavier de Bolle, Te-Din Huang, Laurent Dortet, Youri Glupczynski
Objectives: To describe a novel plasmid-borne class D carbapenemase (CHDL) named OXA-427 identified in several Enterobacteriaceae clinical isolates from nine patients in one Belgian hospital. Methods: OXA-427-producing isolates were analysed by an electrochemical imipenem hydrolysis method (BYG Carba test), Carba NP test, conventional phenotypic assays and by molecular methods (PCR, whole sequencing of the OXA-427-encoding plasmid and cloning). The antimicrobial resistance profile of OXA-427 was analysed by expression of the cloned gene in Escherichia coli DH10B and J53...
September 1, 2017: Journal of Antimicrobial Chemotherapy
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