Center for Magnetic Resonance

J.J. Medvedev, D.V. Semenok, X.V. Azarova, L.L. Rodina, V.A. Nikolaev

“A New Powerful Approach to Multi-Substituted 3(2H)-Furanones via Brønsted Acid-Catalyzed Reactions of 4-Diazodihydrofuran-3-ones”

Synthesis, 2016, 48, A-H
DOI:10.1055/s-0036-1588304

The interaction of 5,5-dialkyl(diaryl)-substituted 4-diazo-3(2H)furanones with Brønsted acids (TFA, TsOH, etc.) causes elimination of nitrogen accompanied by 1,2-nucleophilic rearrangement, giving rise to exclusive formation of 4,5-dialkyl(diaryl)-substituted 3(2Н)-furanones, ring-fused 3(2H)-furanones, and phenanthro[9,10-b]furan-3(2H)-ones in yields of up to 99%. The reaction is a new highly efficient way for the synthesis of multisubstituted 3(2Н)furanones.

D.V. Semenok, J.J. Medvedev, M.S. Avdontceva, S.I. Selivanov, J. Sieler, A.S. Mereshchenko, V.A. Nikolaev

“Experimental Evidence of Intramolecular CAr–H···O=C Hydrogen Bonds in the Structure of (Diaryl)tetrahydrofuranones Using Spectroscopic Tools”

Helvetica Chim. Acta, 2016, 99, 716-723
DOI:10.1002/hlca.201600149

The occurrence of bifurcate H-bonds CAr–H···O=C in the structure of (diaryl)-tetrahydrofuranones was experimentally demonstrated using different methods and techniques. The consistent increasing spin–spin coupling constants 1J(C,H) of the ortho-H-atoms and low-field shift of v (C=O) in IR spectra of 2,2-(diaryl)tetrahydrofuran-3(2H)-ones relative to their 5,5-diaryl counterparts, as well as pronounced dependence of the ortho-C–H H-atoms chemical shifts on the temperature and solvent polarity along with X-ray diffraction analysis data unambiguously point to the existence of weak CAr–H···O=C H-bonds in these molecules.

A.A. Belyaev, D.V. Krupenya, E.V. Grachova, V.V. Gurzhiy, A.S. Melnikov, P.Yu. Serdobintsev, E.S. Sinitsyna, E.G. Vlakh, T.B. Tennikova, S.P. Tunik

“Supramolecular AuI–CuI Complexes as New Luminescent Labels for Covalent Bioconjugation”

Bioconjugate Chem, 2016, 27, 143-150
DOI:10.1021/acs.bioconjchem.5b00563

Two new supramolecular organometallic complexes, namely, [Au₆Cu₂(C₂C₆H₄CHO)₆(PPh₂C₆H₄PPh₂)₃](PF₆)₂ and [Au₆Cu₂(C₂C₆H₄NCS)₆(PPh₂C₆H₄PPh₂)₃](PF₆)₂, with highly reactive aldehyde and isothiocyanate groups have been synthesized and characterized using X-ray crystallography, ESI mass spectrometry, and NMR spectroscopy. The compounds obtained demonstrated bright emission in solution with the excited-state lifetime in microsecond domain both under single- and two-photon excitation. The luminescent complexes were found to be suitable for bioconjugation in aqueous media. In particular, they are able to form the covalent conjugates with proteins of different molecular size (soybean trypsin inhibitor, human serum albumin, rabbit anti-HSA antibodies). The conjugates demonstrated a high level of the phosphorescent emission from the covalently bound label, excellent solubility, and high stability in physiological media. The highest quantum yield, storage stability, and luminance were detected for bioconjugates formed by covalent attachment of the aldehyde-bearing supramolecular AuI–CuI complex. The measured biological activity of one of the labeled model proteins clearly showed that introduced label did not prevent the biorecognition and specific protein–protein complex formation that was extremely important for the application of the conjugates in biomolecular detection and imaging.