| Abstract [eng] |
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. |
