22 research outputs found
A pozitrĂłniumatom kĂ©pzĹ‘dĂ©si valĂłszĂnűsĂ©gĂ©t Ă©s reakciĂłkĂ©szsĂ©gĂ©t befolyásolĂł fizikai Ă©s kĂ©miai tĂ©nyezĹ‘k vizsgálata oldatokban = Study of the physical and chemical factors affecting the formation probability and reactivity of the positronium atom in solutions
A pályázat munkatervĂ©ben megjelölt három tĂ©makörben vĂ©geztĂĽnk kutatásokat. 1. A pozitrĂłniumkĂ©pzĹ‘dĂ©s valĂłszĂnűsĂ©gĂ©nek hĹ‘mĂ©rsĂ©kletfĂĽggĂ©se tiszta oldĂłszerekben A spurfolyamatokra alkalmazott egyszerű, versengĹ‘ reakciĂłkra Ă©pĂĽlĹ‘ modellĂĽnk által elĹ‘re jelzett összefĂĽggĂ©s a vizsgált kĂĽlönbözĹ‘ polaritásĂş tiszta oldĂłszerek mindegyikĂ©ben Ă©rvĂ©nyesnek bizonyult. Meg tudtuk határozni a pozitron ionizáciĂłs nyomában az oldĂłszer-rekombináciĂł Ă©s a pozitrĂłniumkĂ©pzĹ‘dĂ©s egymással versengĹ‘ reakciĂłinak aktiválásienergia-kĂĽlönbsĂ©geit. 2. Az o-Ps atom reakciĂłi spincsapdákkal MegállapĂtottuk, hogy az o-Ps atom mint a legegyszerűbb szabad gyök, a diffĂşziĂłvezĂ©relt reakciĂłkra jellemzĹ‘ sebessĂ©ggel reagál a gyökscavenger tulajdonságĂş nitrozovegyĂĽletekkel mind vĂzben, mind metanolban, ill. azok elegyeiben. Metanol-vĂz elegyekben szoros korreláciĂłt tapasztaltunk a pozitrĂłniumkĂ©pzĹ‘dĂ©s inhibĂciĂłjára jellemzĹ‘ állandĂł (sigma) Ă©s a szolvatált elektronokkal szembeni reakciĂłsebessĂ©gi állandĂł (ke) között. 3. A molekulaszerkezet Ă©s az o-Ps atommal szembeni reakciĂłkĂ©szsĂ©g közötti összefĂĽggĂ©s Szerves vegyĂĽletek hasonlĂł vázszerkezetű molekulákbĂłl állĂł csoportjain (S-hidat tartalmazĂł szerves vegyĂĽletek, ill. tetrazin-származĂ©kok) tanulmányoztuk a pozitrĂłniumatom reakciĂłkĂ©szsĂ©ge Ă©s a molekulák szerkezete közötti kapcsolatot. A mĂ©rt reakciĂłsebessĂ©gi állandĂłk Ă©s a vegyĂĽletek számĂtott LUMO-energiái között igen erĹ‘s korreláciĂłt mutatĂł lineáris összefĂĽggĂ©st kaptunk. | Three topics have been investigated. 1. Temperature dependence of the positronium yields in pure liquids A correlation predicted by our simple model based on the competing reaction scheme of the spur processes proved to be valid in all of the investigated pure liquids of different polarity. It was possible to determine the activation energy differences between the two main competing reaction pathways in the positron spur, i.e., solvent recombination and positronium formation. 2. Reactions of o-Ps with spin traps o-Ps atom, the simplest free radical reacts with a diffusion controlled rate with the radical scavenger type nitroso compounds in methanol-water mixtures. Close correlation was found between the inhibition constant of positronium formation (sigma) and the reaction rate constants (ke) towards the solvated electrons. 3. Correlation between the chemical reactivity of the molecules towards the o-Ps atom and their molecular structure The correlation between the reactivity of o-Ps atom and the molecular structure of some groups of organic compounds with a common framework (S-bridge containing organic molecules or tetrazine derivatives) was investigated. A close linear correlation was observed between the measured reaction rate constants and the calculated LUMO energies of the compounds
Heterociklusos vegyületek átmenetifém-katalizált szintézise = Transition metal catalysed synthesis of heterocyclic compounds
Eljárást dolgoztunk ki nukleofil heterociklusos karbĂ©n (NHC) prekurzorkĂ©nt alkalmazhatĂł heterociklusos vegyĂĽletek moduláris szintĂ©zisĂ©re, amelyek közĂĽl több előállĂtását enantiomertiszta formában is elvĂ©geztĂĽk. ElőállĂtottunk több palladaciklusos katalizátort Ă©s rĂ©szletesen vizsgáltuk ezek szerkezete Ă©s aktivitása kapcsolatát keresztkapcsolási reakciĂłkban. BehatĂłan vizsgáltuk olyan Ăşj, palládiumkatalizált kapcsolási reakciĂłk lehetĹ‘sĂ©gĂ©t, amelyekben a fĂ©morganikus kapcsolĂłpartner fĂ©mrĂ©szletĂ©t szerves csoporttal tudjuk kiváltani. HatĂ©kony eljárást dolgoztunk ki benzo[b]tiofĂ©n-származĂ©kok Ă©s purinszármazĂ©kok ilyen Ăşton valĂł átalakĂtására. Vizsgáltuk az etinil-ciklohexanol, mint acetilĂ©nforrás alkalmazhatĂłságát diaril-acetilĂ©nek Ă©s benzofurán-származĂ©kok előállĂtásában. Ăšj palládiumkatalizált reakciĂłutat dolgoztunk ki benzofurán-származĂ©kok előállĂtására. Vizsgáltuk a piridazino[4,5-d]piridazin rendszeren poláris fĂ©morganikus reagensekkel kiválthatĂł reakciĂłt. TetrazinszármazĂ©kok Ă©s nukleofil karbĂ©nek reakciĂłját vizsgálva elsĹ‘kĂ©nt Ărtuk le kinoidális tetrazinvegyĂĽletek szintĂ©zisĂ©t. Sikeresen megvalĂłsĂtottuk több Ăşj tĂpusĂş fluoreszcens jelzĹ‘t hordozĂł makrociklus szintĂ©zisĂ©t Ă©s vizsgáltuk az inherens fluoreszcencia-letörĂ©st ezen rendszerekben, valamint alkalmazhatĂłságukat a molekuláris felismerĂ©sben. ElsĹ‘kĂ©nt Ărtunk le egy Ăşj, a konformáciĂłs dinamikán alapulĂł szenzorcsaládot. | We developed a new procedure for the preparation of nucleophilic heterocyclic carbene precursors and synthesized a series of chiral enantiopure NHCs. We prepared a series of palladacycles and studied the effect of their structure on their catalytic activity in cross coupling reactions. We studied such palladium catalysed processes where the organometallic coupling partner can be exchanged for an organic moiety. We developed an efficient transformation on benzo[b]thiophen and purine derivatives. We studied the use of 1-ethynyl-cyclohexanol as acetylene surrogate in the preparation of diarylacetylenes and benzofurane derivatives. We edeveloped a new palladium catalysed route for the synthesis of benzofurane derivatives. We studied the reactivity of pyridazino[4,5-d]pyridazines with polar organometallic reagents. We were the first to describe the synthesis of quinoidal tetrazine derivatives in the reaction of tetrazines with nucleophilic carbenes. We synthesized a series of macrocyclic heterocycles bearing different fluorescent markers and studied their inherent fluorescence quenching and their utility in molecular recognition. We were the first to described a new sensor family working on the principle of molecular dynamics
Efficient Copper-Catalyzed Trifluoromethylation of Aromatic and Heteroaromatic Iodides: The Beneficial Anchoring Effect of Borates
Efficient copper
-
catalyzed trifluoromethylation of aromatic iodides was achieved with
TMSCF
3
in the presence of
trimethoxyborane. The Lewis acid was used to anchor the in situ generated trifluoromethyl anion and suppress its rapid decomp
os
i-
tion. Broad applicability of the new trifluoromethylating reaction was demonstrated in the functionali
zation of different aromatic
and heteroaro
matic iodides
Synthesis and serum protein binding of novel ring-substituted harmine derivatives
A series of new derivatives of the natural β-carboline alkaloid harmine, introducing hydrophobic substituents into positions 7 and 9 were synthetized as potential anticancer agents. Their binding affinities for human serum albumin (HSA) and α1-acid glycoprotein (AAG) were investigated by affinity chromatography combined with fluorescence, circular dichroism (CD) and UV absorption spectroscopy. The weak binding of harmine to both proteins (Ka ~ 3 × 104 M-1) was highly increased by aromatic substitutions (Ka ~ 105-106 M-1). Derivatives having a substituted benzyl group in the N9-position of the β-carboline nucleus showed about tenfold and hundredfold affinity enhancement for HSA and AAG, respectively. Such a strong plasma protein interaction would be of pharmacokinetic relevance for these potential drug candidates. Induced CD spectra indicated the variant selective, dimeric binding of the 7-pyridylethoxy derivative to AAG. Absorbance and fluorescence spectra refer to the binding preference of the neutral form of the studied β-carbolines for both proteins
Establishing Drug Discovery and Identification of Hit Series for the Anti-apoptotic Proteins, Bcl-2 and Mcl-1
We describe our work to establish structure- and fragment-based drug discovery to identify small molecules that inhibit the anti-apoptotic activity of the proteins Mcl-1 and Bcl-2. This identified hit series of compounds, some of which were subsequently optimized to clinical candidates in trials for treating various cancers. Many protein constructs were designed to identify protein with suitable properties for different biophysical assays and structural methods. Fragment screening using ligand-observed NMR experiments identified several series of compounds for each protein. The series were assessed for their potential for subsequent optimization using 1H and 15N heteronuclear single-quantum correlation NMR, surface plasmon resonance, and isothermal titration calorimetry measurements to characterize and validate binding. Crystal structures could not be determined for the early hits, so NMR methods were developed to provide models of compound binding to guide compound optimization. For Mcl-1, a benzodioxane/benzoxazine series was optimized to a Kd of 40 ÎĽM before a thienopyrimidine hit series was identified which subsequently led to the lead series from which the clinical candidate S 64315 (MIK 665) was identified. For Bcl-2, the fragment-derived series were difficult to progress, and a compound derived from a published tetrahydroquinone compound was taken forward as the hit from which the clinical candidate (S 55746) was obtained. For both the proteins, the work to establish a portfolio of assays gave confidence for identification of compounds suitable for optimization
A gyógyszerkutatás új irányzatai: hatékonyság és biztonságosság = New Directions in Drug Discovery: Safety and Efficiency
A betegsĂ©gek mögött meghĂşzĂłdĂł biokĂ©miai, sejtbiolĂłgiai változások molekuláris szintű megĂ©rtĂ©se a korszerű gyĂłgyszerkutatás alapját kĂ©pezi. A kiválasztott biolĂłgiai cĂ©lpont, leggyakrabban egy fehĂ©rje, működĂ©sĂ©nek gátlásátĂłl vagy fokozásátĂłl azt remĂ©ljĂĽk, hogy elĹ‘segĂti a gyĂłgyulást. A hagyományos gyĂłgyszerkutatási megközelĂtĂ©sek molekuláris alapját a kiválasztott fehĂ©rjĂ©vel valĂł közvetlen kölcsönhatás jelentette. Ugyanakkor a sejten belĂĽli molekuláris biolĂłgiai folyamatok rĂ©szletesebb megĂ©rtĂ©se több Ăşj megközelĂtĂ©st nyitott a gyĂłgyszerkutatás számára. A közlemĂ©ny ezeket a gyĂłgyszerkutatási irányzatokat mutatja be, kĂĽlön kitĂ©rve biztonságosságukra
Metal-Ligand Cooperativity with Nickel Pincer Complexes
In this thesis work, the synthesis of a nickel-pincer complex, and its reactivity towards different types of bonds is presented, exploiting the possibility of metal-ligand cooperation in our complex. First, the optimization of the ligand synthesis is shown, then a variety of different test reactions and their results are presented