Author, Institution: Arminas Urbonavičius, Kaunas University of Technology
Science area, field of science: Natural Sciences, Chemistry, N003
Scientific Supervisor: Senior Researcher Dr. Sonata Krikštolė (Kaunas University of Technology, Natural Sciences, Chemistry, N003)
Scientific Advisor: Prof. Dr. Eglė Arbačiauskienė (Kaunas University of Technology, Natural Sciences, Chemistry, N003)
Dissertation Defense Board of Chemistry Science Field:
Prof. Dr. Vytautas Getautis (Kaunas University of Technology, Natural Sciences, Chemistry, N003) – chairperson
Senior Researcher Dr. Marytė Daškevičienė (Kaunas University of Technology, Natural Sciences, Chemistry, N003)
Chief Researcher Dr. Linas Labanauskas (State Research Institute Center for Physical Sciences and Technology, Natural Sciences, Chemistry, N003)
Assoc. Prof. Dr. Jolanta Rousseau (Artois University, France, Natural Sciences, Chemistry, N003)
Dr. Ingrida Tumosienė (Kaunas University of Technology, Natural Sciences, Chemistry, N003)
Dissertation defense meeting will be at Rectorate Hall of Kaunas University of Technology (K. Donelaičio 73-402, Kaunas)
The doctoral dissertation is available at the library of Kaunas University of Technology (Gedimino 50, Kaunas) and on the internet: A. Urbonavičius el. dissertation (PDF)
Annotation: For the first time, new 6-(hetero)aryl-2-phenyl-5-hydroxypyrano[2,3-c]pyrazole-4(2H)-ones were synthesized through four reaction stages when using readily available 1-phenyl-1H-pyrazol-3-ol. In this synthesis, (E)-1-(3-hydroxy-1-phenyl-1H-pyrazol-4-yl)-3-(hetero)arylprop-2-en-1-ones were employed in reactions with hydroxylamine to obtain pyrazole-isoxazoles. Additionally, a 15N-labeled 3/5-(3-methoxy-1-phenyl-1H-pyrazol-4-yl)-5/3-phenyl-15N-1,2-oxazole was synthesized. The introduction of the 15N isotope into azaheterocycles is an important method for studying molecular structures, thereby significantly expanding the possibilities of using NMR methods. O-alkynylation reactions of 5-hydroxypyrano[2,3-c]pyrazol-4(2H)-ones were performed to obtain 2,6-diphenyl-5-methoxypyrano[2,3-c]pyrazol-4(2H)-one, 2-phenyl-6-(1-methylpyridin-1-ium-4-yl)-4-oxo-2,4-dihydropyrano[2,3-c]pyrazol-5-olate, and 2-phenyl-6-(1-methylpyridin-1-ium-3-yl)-4-oxo-2,4-dihydropyrano[2,3-c]pyrazol-5-olate. By performing Pd-catalyzed reactions with 5-trifluoromethanesulfonate, the corresponding new 5-alkenyl-, 5-alkynyl-, and 5-arylhydroxypyrano[2,3-c]pyrazol-4(2H)-ones were obtained. The crystal of the obtained compound, 2-phenyl-6-(1-methylpyridinium-4-yl)-4-oxo-2,4-dihydropyrano[2,3-c]pyrazol-5-olate, was grown, and X-ray diffraction analysis was performed. The compound was assigned the CCDC-2287991 code in the CSD database. The newly synthesized compounds contribute to the library of organic chemistry compounds which are potentially applicable in the creation of more complex molecules and which are subject to biological activity investigations. The photophysical studies of the compounds showed the ability of pyrano[2,3-c]pyrazole-4(2H)-ones to exhibit dual-emission fluorescence with a large Stokes shift. The structures of these compounds can be further explored for potential applications as biomarkers.
June 18 d. 14:00
Rectorate Hall at Kaunas University of Technology (K. Donelaičio 73-402, Kaunas)
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