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Search results for: B-LACTAM
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PHYSICAL REVIEW B
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A new approach to the stereoselective synthesis of trans-3-carbamoyl-b-lactam moieties†
PublicationOne-pot synthesis of optically active 1,4-disubstituted-3-carbamoyl-azetidinones from 5-[(N-arylamino)- (hydroxyl)methylene]-2,2-dimethyl-1,3-dioxa-4,6-diones and chiral aldimines is achieved via thermal generation of carbamoyl ketenes and subsequent [2+2] cycloaddition. Three possible chiral induction approaches were tested and (R)-(+)-1-phenylethylamine was confirmed as the best chiral auxiliary. Among the four possible diastereoisomers,...
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One-Step Synthesis of b-Lactams with Retro-Amide Side Chain
PublicationAbstract: A one pot synthesis for preparation of 1,4-disubstituted-2-oxo-azetidine-3-carboxylic acid amides was developed. 5-(α-N-substituted-amino-α'-hydroxy)methylene Meldrum's acids act as a source of ketenes that react with aldimines in boiling toluene to give b-lactams with retro-amid side chain.
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JOURNAL OF PHYSICAL CHEMISTRY B
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Synthesis of 3-Carbamoyl b-Lactams via Manganese(III)-Promoted Cyclization of N-Alkenylmalonamides
PublicationManganese(III)-promoted cyclization of N-alkenylmalonamides (¼N-alkenylpropanediamides) gave 3-(aryl/(alkylamino)carbonyl) b-lactams as well as 3-(aryl/(alkylamino)thiocarbonyl) b-lactams. The relative configuration of the obtained products was unambiguously determined by X-ray crystallography. The proposed method is very useful for the one-pot synthesis of a number of 3-(aryl/ (alkylamino)carbonyl) b-lactams, especially those...
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SENSORS AND ACTUATORS B-CHEMICAL
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APPLIED CATALYSIS B-ENVIRONMENTAL
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ACTA PHYSICA POLONICA B
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COMPOSITES PART B-ENGINEERING
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<b><i>CTLA4</i></b> and <b><i>CD28</i></b> Gene Polymorphisms with Respect to Affective Symptom Domain in Schizophrenia
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Węzły grupy B
PublicationWęzły grupy B są budowane na przecięciach dróg, z których jedna - z definicji - nie może mieć punktów kolizji, na drugiej natomiast są one dopuszczalne. Węzeł taki oznacza zazwyczaj połączenie drogi ruchu szybkiego z drogami podrzędnymi. Oczywiście, nawet na przecięciu dróg ogólnodostępnych może być zastosowany węzeł grupy A - czyli węzeł całkowicie bezkolizyjny, o ile natężenia i ranga krzyżujących się dróg uzasadniają przyjecie...
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Structure elucidation of carbamoylo-β-lactam diastereoisomers by ROESY and NOESY experiments
PublicationRecently we have focused in the problem of preparation of carbamoylo-β-lactams as a result of oxidative cyclization of malonyl enamides. In our experiments we obtain mixture of two main β-lactam products: as a result of subsequent elimination and a second as a product of substitution. All of the produced β-lactams have trans configuration what was confirmed by 1H coupling constants. However id should be stressed that in the case...
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Stereochemical Assingment of β -lactam Antibiotics and their Analogues by Electronic Circular Dichroism Spectroscopy
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JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
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Thermal properties of terpoly(ester-b-ether-b-amide)s with aliphatic ester blocks
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Acta Pharmaceutica Sinica B
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Sequences of fixed point indices of iterations in dimension 2.
PublicationW pracy dowodzi się, że każdy ciąg liczb całkowitych spełniający relacje Dolda może zostać zrealizowany jako ciąg indeksów punktu stałego iteracji ciągłego odwzorowania dwuwymiarowego dysku w siebie.
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TaRh 2 B 2 and NbRh 2 B 2 : Superconductors with a chiral noncentrosymmetric crystal structure
PublicationIt is a fundamental truth in solid compounds that the physical properties follow the symmetry of the crystal structure. Nowhere is the effect of symmetry more pronounced than in the electronic and magnetic properties of materials—even the projection of the bulk crystal symmetry onto different crystal faces is known to have a substantial impact on the surface electronic states. The effect of bulk crystal symmetry on the properties...
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Characterization and Wear Response of Magnetron Sputtered W–B and W–Ti–B Coatings on WC–Co Tools
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The influence of chemical composition of amide block on the thermal properties and structure of terpoly(ester-b-ether-b-amide) elastomers
PublicationMultiblock terpolymers-(PBT-b-PTMO-b-PA12,10)(n)- constituting the polymer systems, in which one of the three blocks (PBT) does not dissolve in PA12,10 block (hard phase) and, depending on its molecular weight is slightly soluble in PTMO block (soft phase), have been obtained. The DSC method was applied to investigate the thermal properties of these polymers and it was found that PBT block acts as an element that produces stiffness...
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B-ENT
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Electron collision with B(CD3)3 molecules
PublicationArtykuł prezentuje całkowite przekroje czynne na rozpraszanie elektronów na drobinach B(CD3)3 zmierzone dla niskich i średnich energii zderzenia. Wyniki porównano z elastycznymi i jonizacyjnymi przekrojami czynnymi obliczonymi dla drobiny B(CD3)3 dla średnich energii zderzenia. Porównano i przedyskutowano przekroje czynne dla drobin zawierających bor.
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Production and characterization of MWBNNT and B-doped SWCNT
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The Lack of Association between <b><i>FCN2</i></b> Gene Promoter Region Polymorphisms and Dental Caries in Polish Children
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Rotating Magnetic Field Increases β-Lactam Antibiotic Susceptibility of Methicillin-Resistant Staphylococcus aureus Strains
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Preparation of bicyclic β-lactam and bicyclic 1,3- oxazinone scaffolds using combined cycloaddition and metathesis processes
PublicationA simple, efficient two-step method for the preparation of heterobicyclic compounds was developed. Starting from 5-acyl or 5-carbamoyl-2,2- dimethyl-1,3-dioxa-4,5-dione bicyclic scaffolds of 1-azabicyclo[5.2.0]non- 3-en-9-one, 6,9,10,10a-tetrahydro-4H-[1,3]oxazino[3,2-a]azepin-4-one, and 6,9,10,10a-tetrahydro-2H-[1,3]oxazino[3,2-a]azepine-2,4(3H)-dione were prepared using cycloaddition of thermally generated ketenes to aldimines...
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Activation of N2O and SO2 by the P–B Bond System. Reversible Binding of SO2 by the P–O–B Geminal Frustrated Lewis Pair
PublicationHerein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P−B bond and formation of a P−O−B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively.
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NbIr 2 B 2 and TaIr 2 B 2 – New Low Symmetry Noncentrosymmetric Superconductors with Strong Spin–Orbit Coupling
PublicationSuperconductivity was first observed more than a century ago, but the search for new superconducting materials remains a challenge. The Cooper pairs in superconductors are ideal embodiments of quantum entanglement. Thus, novel superconductors can be critical for both learning about electronic systems in condensed matter and for possible application in future quantum technologies. Here two previously unreported materials, NbIr2B2...
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Ni2X2 (X=pnictide, chalcogenide, or B) based superconductors
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Amphotericin B and Its New Derivatives - Mode of Action
PublicationAmphotericin B (AmB) is a well known antifungal and antiprotozoal antibiotic used in the clinic for several decades. Clinicalapplications of AmB, however, are limited by its nephrotoxicity and many other acute side effects which are not acceptable by patientswhen their life is not threaten. In order to improve the therapeutic index of this drug, lipid formulations have been introduced and manyefforts have been made to obtain less...
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Ni2X2 (X = pnictide, chalcogenide, or B) based superconductors
PublicationPublikacja jest przeglądem właściwości nadprzewodników na bazie niklu, które zawierają płaszczyzny Ni2X2 (X=As, P, Bi, Si, Ge, B).
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Genetic Variability of Hepatitis B Virus Isolates in Poland
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Study of radioluminescence in LiMgPO4 doped with Tb, B and Tm
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Preparation and photocatalytic activity of B-doped titanium dioxide
PublicationOtrzymano TiO2 domieszkowany borem, aktywny w reakcjach fotodegradacji pod wpływem światła widzialnego (λ>400 nm). Fotokatalizatory otrzymano poprzez hydrolizę tytanianu(IV) izopropylu w obecności związków boru lub poprzez ucieranie ST-01 z prekursorami B i następnie kalcynację w temperaturze 450stC. Jako źródło boru zastosowano kwas borowy (0,5 i 10%wag.) lub trietylo ester kwasu borowego (0,5; 1; 5 i 10%wag.). Najwyższą aktywność...
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Algorytmy numeryczne obliczania pseudokątów wiążących typu B
PublicationReferat tematycznie związany jest z teoretycznymi podstawami funkcjonowania technologii pomiarowej bazującej na stanowiskach swobodnie zorientowanych. Przedstawiono algorytmy obliczania pseudoobserwacji kątowych typu B (zwanych pseudokątami), wiążącymi sieć punktów odniesienia ze stanowiskami pomiarowymi. Pseudokąty wiążące typu B wykorzystuje się w sieciach obliczeniowych typu B.
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WEAR OF Si OR B DOPED AMORPHOUS CARBON COATINGS
PublicationThe paper describes a complex wear research on DLC (amorphous carbon) moped with boron (B) and silicone (Si). The tests were carried out in two different sliping systems: flat–on–flat (ring contact, unidirectional sliding) and ball–on–flat (reciprocating sliding). Water and medical saline solutions were used as lubricants. A comparative analysis of the results revealed differences in the initiation and progress of wear and the...
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Novel primosomal protein B from Clostridium pasteurianum
PublicationPriB is a primosomal protein that catalyzes DNA replication in Procaryota. The replication pathway starts with PriA protein - the initiator protein that binds to a DNA replication fork, unwinds double-stranded DNA and role of PriB is to stabilize PriA on the DNA. However there are many biochemical differences in replication mechanism in bacteria and only some of them use PriB proteins. A few of PriB proteins were published and...
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Novel primosomal protein B from Clostridium pastuerianum
PublicationPriB is a primosomal protein that catalyzes DNA replication in Procaryota. The replication pathway starts with PriA protein - the initiator protein that binds to a DNA replication fork, unwinds double-stranded DNA and role of PriB is to stabilize PriA on the DNA. However there are many biochemical differences in replication mechanism in bacteria and only some of them use PriB proteins. A few of PriB proteins were published and...
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Modyfikacje chemiczne Amfoterycyny B i Nystatyny A1
PublicationW ramach badań, opisanych w niniejszej rozprawie doktorskiej, przetestowano możliwości chemicznej modyfikacji części aminocukrowej aglikonu amfoterycyny B i nystatyny A1. Otrzymano chroniony aglikon AmB, posiadający grupę hydroksylową na atomie węgla C19, który posłużył jako substrat w reakcji substytucji nukleofilowej oraz dehydracyjnej glikozylacji. Opracowano i zoptymalizowano warunki syntezy chronionych pochodnych cukrowych,...
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Ipertrofan Revisited—The Proposal of the Complete Stereochemistry of Mepartricin A and B
PublicationBeing a methyl ester of partricin, the mepartricin complex is the active substance of a drug called Ipertrofan (Tricandil), which was proven to be useful in treatment of benign prostatic hyperplasia and chronic nonbacterial prostatitis/chronic pelvic pain syndrome. Nevertheless, no direct structural evidence on the stereochemistry of its components has been presented to date. In this contribution, we have conducted detailed, NMR-driven...
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COLLOIDS AND SURFACES B-BIOINTERFACES
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Photocatalytic activity of TiO2 polymorph B revisited: physical, redox, spectroscopic, and photochemical properties of TiO2(B)/anatase series of titanium dioxide materials
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N-(1-Piperidinepropionyl)amphotericin B methyl ester (PAME) - a new derivative of the antifungal antibiotic amphotericin B: Searching for the mechanism of its reduced
PublicationZ zastosowaniem techniki monowarstw Langmuira zbadano naturę oddziaływań pochodnej antybiotyku przeciwgrzybowego amfoterycyny B o obniżonej toksyczności tj. estru metylowego N-(1-piperydynopropionylo)amfoterycyny B (PAME) z komponentami błon biologicznych takich jak: ergosterol, cholesterol i modelowy fosfolipid DPPC i stwierdzono, że zróżnicowanie tych oddziaływań jest podstawą obniżonej toksyczności związku.
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Updates in the Metabolism of Lactic Acid Bacteria
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Regulation of carbon catabolism in Lactococcus lactis
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Studies on the complex formation between lactams and thiolactams of sparteine with copper(II) cation
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Simple and novel synthesis of 3-(thio)phosphoryl-β-lactams by radical cyclization
PublicationRadical cyclization of phosphono-acetenamides promoted by manganese(III) acetate leads exclusively to the formation of 3-phosphoryl-β-lactams. The thiophosphoryl analogues were also prepared using this method. In particular, the presented protocol does not require the use of noble metals, while comparable methods do.
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Narzędzia do kontroli jakości powietrza wewnętrznego / B. Zabiegała
PublicationPrzyjmuje się, że dorosły człowiek średnio 60% swojego życia spędza w domu, 30% w pracy, 5% w różnego rodzaju środkach transportu a tylko 3% na zewnątrz pomieszczeń. Powyższe liczby wskazują, że powietrze wewnętrzne może w istotny sposób oddziaływać na stan zdrowia i samopoczucie człowieka. Szeroko rozumiana kontrola jakości powietrza wewnętrznego jest więc niezbędnym elementem w zapewnieniu komfortu życia użytkownikom pomieszczeń...
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Current molecular methods for the detection of hepatitis B virus quasispecies
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Efficient production of B-substituted single-wall carbon nanotubes
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