11 research outputs found
Selective Heterogeneous Catalytic Hydrogenation of Nitriles to Primary Amines
Primary amines are important intermediates, especially in the area of pharmaceutical, plastic and agrochemical industry. The heterogeneous catalytic hydrogenation of nitriles is one of the most frequently applied process for the synthesis of diverse amines. However, the control of the selectivity is a critical issue in this reaction. Over the past decade, many studies have been reported using heterogeneous transition metal catalysts for the selective reduction of nitriles to the corresponding primary amines. The type of the catalysts, especially, the chemical nature of metals in the catalysts is one of the most important factors to influence the selectivity, the reaction rate, and possibly also the reaction pathway and the deactivation of the catalyst. Thus, this review focuses on the heterogeneous transition metal catalysts and summarizes the recent developments achieved in the selective catalytic hydrogenation of nitriles to primary amines
Atomi topológiai elrendeződés: a potenciális energia és az elektronszerkezet kapcsolata = Atomic topological arrangement: relation between the potential energy and the electronic structure
A szĂ©natomok szomszĂ©dsági viszonyait felhasználva topolĂłgiai koordinátákat adtunk meg hengeres spirális Ă©s toroidalis nanocsövekre. Magyarázatot adtunk a kĂĽlönfĂ©le alakĂş nanocsĹ‘ szerkezetek geometriai okaira. A csĂşcspontok bármely számozásátĂłl fĂĽggetlen olyan gráfelmĂ©leti eljárást javasoltunk királis poliĂ©derek, poliĂ©der alakĂş molekulák vagy gráfok kiralitásának leĂrására amely megkĂĽlönbözteti a kĂ©t enantiomert. Megoldottuk nanocsĹ‘ elágazások szerkesztĂ©sĂ©nek a problĂ©máját. A Cox-Thompson inverz szĂłrás problĂ©mát megoldottuk fázis tolások vĂ©ges halmazának alkalmazásával. Egyszerű eljárást javasoltunk szoliton gerjesztĂ©sek vizsgálatára kĂ©t komponensű Bose-Einstein kondenzátumokra. Az elsĹ‘ Born közelĂtĂ©s alapján Ăşj közelĂtĹ‘ mĂłdszert vezettĂĽnk be csatolt csatornás kvantumos szĂłrás problĂ©ma invertálására lokális csatolási potenciál Ă©s rögzĂtett energia esetĂ©n. Háromszög Ă©s nĂ©gyszög alakĂş atomi konfiguráciĂłkat találtunk amorf szilĂcium gĹ‘z fázisĂş lerakĂłdásának szoros kötĂ©sű modellezĂ©sekor. KimerĂtĹ‘ magyarázatot adtunk kalkogĂ©n ĂĽvegek fotoindukált tĂ©rfogati változásaira. LeĂrtuk a három-, nĂ©gy- Ă©s n-qubit összefonĂłdottság geometriáját. Kapcsolatot találtunk a fonalas fekete lyukak Ă©s az összefonĂłdottság geometriája között. A rĂ©z (001) felĂĽletre rakott kobalt monorĂ©teg magnon spektrumának hosszĂş hullámhosszĂş viselkedĂ©sĂ©t vizsgáltuk elsĹ‘ elveken alapulĂł mĂłdszerrel. | Using the neighboring conditions of carbon atoms we gave topological coordinates for tubular, helical and toroidal nanotubes. We gave explications for various nanotube structures from geometric point of view. A graph-theoretical procedure is proposed for assigning a chirality descriptor to each enantiomer of a chiral polyhedron, polyhedral molecule or graph, independently of any vertex labeling scheme. We have solved the problem of nanotube junction construction. A solution was given for the Cox-Thompson inverse scattering problem using finite set of phase shifts. A simple method is presented to analyze the stability of static solitonic excitations of two-component Bose-Einstein condensates. An approximative method based on the first Born approximation is developed for the solution of the quantum inverse scattering problem at fixed energy for coupled reaction channels. Triangular and square atomic configurations were found in a tight-binding simulation of a-Si networks by vapor deposition processes. We gave a comprehensive explanation of photoinduced volume changes in chalcogenide glasses. We described the geometry of three-, four- and n-qubit entanglement. We have found a relation between stringy black holes and the geometry of entanglement. The long wavelength behavior of the magnon spectrum for Co monolayer on Cu(001) was investigated from first principle
Poisoning and Reuse of Supported Precious Metal Catalysts in the Hydrogenation of N-Heterocycles, Part II: Hydrogenation of 1-Methylpyrrole Over Rhodium
Poisoning effect of nitrogen on heterogeneous, supported precious metal catalysts, along with their recycling, was further examined in the liquid-phase hydrogenation of 1-methylpyrrole (MP) to 1-methylpyrrolidine (MPD) over rhodium on carbon or γ-alumina, in methanol, under non-acidic conditions, at 25–50 °C and 10 bar. Reusing a spent, unregenerated 5% Rh/C or 5% Rh/γ-Al2O3 catalyst, it was found that the conversion of this model substrate and the activity of the catalyst were strongly dependent on the amount of catalyst, the type of support, the catalyst pre- or after-treatment, the temperature, and the number of recycling, respectively. An unexpected catalytic behaviour of rhodium was observed when it was used in a prehydrogenated form, because no complete conversion of MP was achieved over even the fresh Rh/C or Rh/γ-Al2O3, contrary to the untreated one. In addition, there was a significant difference in the reusability and activity of these rhodium catalysts, depending on their supports (activated carbon, γ-alumina). These diversions were elucidated by applying dispersion (O2- and H2-titration), temperature-programmed desorption of ammonia (NH3-TPD), and transmission electron microscopy (TEM) measurements
ReakciĂłkörĂĽlmĂ©nyek optimálása Ăşj tĂpusĂş szelenenil-szulfid kötĂ©st tartalmazĂł szĂ©nhidrát-származĂ©kok előállĂtására
KutatĂłcsoportunk korábban már beszámolt olyan aromás maghoz Ă©pĂtett diszubsztituált glikozil-diszulfidokrĂłl, melyek hatásosnak bizonyultak a Trypanosoma cruzi egysejtűvel szemben.
KutatĂłmunkám során egy központi benzol, illetve egy naftalin maghoz szelenenil-tio-metilĂ©n kötĂ©sekkel kapcsolt D-glĂĽko-, Ă©s D-galakto-konfiguráciĂłjĂş monoszacharid egysĂ©geket tartalmazĂł, divalens szĂ©nhidrát-származĂ©kok előállĂtását terveztem megvalĂłsĂtani.
A naftalin Ă©s benzol 1,4-bisz(metántioszulfonátometil)-származĂ©kokat enyhe körĂĽlmĂ©nyek között (szobahĹ‘mĂ©rsĂ©kleten), aprotikus-poláris dimetil-formamidban, trietil-amin savmegkötĹ‘ jelenlĂ©tĂ©ben nukleofil szubsztitĂşciĂłs reakciĂłkban reagáltattuk β-D-glikopiranozil-szelenourĂłnium sĂłkkal. A reakciĂł eredmĂ©nyekĂ©nt a kapcsolási reakciĂłkkal párhuzamosan egy versengĹ‘ oxidáciĂłs folyamat is lejátszĂłdott, melynek során a sĂłbĂłl felszabadulĂł glikozil-1-szelenolátbĂłl szimmetrikus diglikozil-diszelenid kĂ©pzĹ‘dött. Ezen nem kĂvánatos jelensĂ©g visszaszorĂtását cĂ©lzĂł kĂsĂ©rleti fázisokon keresztĂĽl igyekeztem megtalálni azon befolyásolĂł tĂ©nyezĹ‘ket, melyek hatással lehetnek az oxidáciĂł sebessĂ©gĂ©re.
Az optimalizálási folyamatok eredmĂ©nyekĂ©ppen vĂ©gĂĽl sikerĂĽlt hatĂ©kony mĂłdszert kifejlesztenem annak Ă©rdekĂ©ben, hogy a szimmetrikus diglikozil-diszelenid csak elhanyagolhatĂł mennyisĂ©gben keletkezzen. Felhasználva a kĂ©t, kompetitĂv reakciĂł sebessĂ©gĂ©nek a koncentráciĂłfĂĽggĂ©sĂ©t, megállapĂtottam, hogy az oxidáciĂł visszaszorĂtása Ă©rdekĂ©ben jelentĹ‘sen növelnem kell az oldĂłszer mennyisĂ©gĂ©t, Ă©s ezzel egyidejűleg a szubsztrátumot is nagy feleslegben kell alkalmaznom.
A laboratĂłriumi körĂĽlmĂ©nyek optimálása rĂ©vĂ©n sikeresen szintetizáltam a tervezett monoszubsztituált vegyĂĽletek közĂĽl az 1-(2,3,4,6-tetra-O-acetil-β-D-glĂĽkopiranozil-szelenenil-tio-metil)-4-(metántioszulfonátometil)-naftalin Ă©s az 1-(2,3,4,6-tetra-O-acetil-β-D-galaktopiranozil-szelenenil-tio-metil)-3-(metántioszulfonátometil)-benzol vegyĂĽleteket, Ă©s NMR spektroszkĂłpia segĂtsĂ©gĂ©vel meghatároztam a szerkezetĂĽket.BSc/BAVegyĂ©szmĂ©rnökg
Application of supported lanthanum catalysts in the hydrogenation of nitriles
International audienceAbstract Nickel and lanthanum on MgO or MgO–Al 2 O 3 catalysts were prepared and characterized. The applicability of the catalysts was studied in the liquid-phase hydrogenation of benzonitrile. A La/MgO catalyst showed surprisingly high activity and selectivity. The scope of the reaction was extended to other nitriles (benzyl cyanide, cinnamonitrile, adiponitrile) over this La/MgO catalyst
Efficient syntheses of zoledronic acid as an active ingredient of a drug against osteoporosis
<p>The reaction of 1<i>H</i>-imidazol-1-ylacetic acid and two equivalents of phosphorus trichloride/phosphorous acid at 75 °C in sulfolane, or in the presence of catalytic amounts of [bmim][BF<sub>4</sub>] afforded zoledronic acid in yields up to 75%. The joint use of the ionic liquid additive and sulfolane as the solvent was synergetic affording highly valuable zoledronic acid in a record yield of 93%.</p
Egis-11150 : A candidate antipsychotic compound with procognitive efficacy in rodents
Classical antipsychotics, e.g. haloperidol, chlorpromazine, are potent at controlling the positive symptoms of schizophrenia but frequently elicit extrapyramidal motor side-effects. The introduction of atypical antipsychotics such as risperidone, olanzapine and clozapine has obviated this problem, but none of the current drugs seem to improve the cognitive deficits accompanying schizophrenia. Thus there is an unmet need for agents that not only suppress the psychotic symptoms but also ameliorate the impairment of cognition. Here, we report the preclinical properties of a candidate antipsychotic, Egis-11150, that shows marked pro-cognitive efficacy. Egis-11150 displayed high affinity for adrenergic alpha(1), alpha(2c), 5-HT(2A) 5-HT(7), moderate affinity for adrenergic alpha(2a) and D(2) receptors. It was a functional antagonist on all of the above receptors, with the exception of 5-HT(7) receptors, where it was an inverse agonist. Phencyclidine-induced hypermotility in mice and inhibition of conditioned avoidance response in rats were assessed to estimate efficacy against the positive and social withdrawal test in rats was used to predict efficacy against the negative symptoms of schizophrenia. Passive-avoidance learning, novel object recognition and radial maze tests in rats were used to assess pro-cognitive activity, while phencyclidine-induced disruption of prepulse inhibition in mice was examined to test for effects on attention. Egis-11150 (0.01-0.3 mg/kg, ip.) was effective in all of the preclinical models of schizophrenia examined. Moreover, a robust pro-cognitive profile was apparent. In summary, work in preclinical models indicates that Egis-11150 is a potential treatment for controlling the psychosis as well as the cognitive dysfunction in schizophrenia. This article is part of a Special Issue entitled 'Cognitive Enhancers'