Počet záznamů: 1
Ascorbigen A—NMR identification
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SYSNO ASEP 0507455 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Ascorbigen A—NMR identification Tvůrce(i) Sychrovský, Vladimír (UOCHB-X) RID, ORCID
Šaman, David (UOCHB-X) RID, ORCID
Fiala, R. (CZ)
Humpa, O. (CZ)
Sýkora, Jan (UCHP-M) RID, ORCID, SAI
Kessler, P. (DE)
Blechta, Vratislav (UCHP-M) RID, ORCID, SAI
Dobrev, Petre (UEB-Q) RID, ORCID
Schraml, Jan (UCHP-M) RID, ORCID, SAIZdroj.dok. Magnetic Resonance in Chemistry. - : Wiley - ISSN 0749-1581
Roč. 57, č. 12 (2019), s. 1084-1096Poč.str. 13 s. Jazyk dok. eng - angličtina Země vyd. GB - Velká Británie Klíč. slova 13C NMR ; 13C–13C coupling constants ; 13C–1H coupling constants ; 1H NMR ; 1H–1H coupling constants ; natural product ; NMR ; NOE ; rotamers ; stereochemistry Vědní obor RIV CF - Fyzikální chemie a teoretická chemie Obor OECD Physical chemistry Vědní obor RIV – spolupráce Ústav chemických procesů - Fyzikální chemie a teoretická chemie CEP GA15-12719S GA ČR - Grantová agentura ČR GA16-10948S GA ČR - Grantová agentura ČR GA19-13436S GA ČR - Grantová agentura ČR Způsob publikování Omezený přístup Institucionální podpora UOCHB-X - RVO:61388963 ; UCHP-M - RVO:67985858 ; UEB-Q - RVO:61389030 UT WOS 000473987100001 EID SCOPUS 85068378971 DOI 10.1002/mrc.4890 Anotace The connectivities of all atoms in ascorbigen A, an important metabolite, were determined unambiguously for the first time. The connectivity between carbon atoms was established by 2D INADEQUATE, and one‐bond 13C–13C coupling constants were determined for all pairs of directly connected carbon atoms except for two strongly coupled carbon pairs. The 13C–13C coupling in one of the pairs was proved by a modification of standard INADEQUATE, however, the signals from the other pair were too weak to be observed. The connectivity within the two strongly coupled C–C pairs was confirmed by a combination of COSY and gHSQC, the latter experiment also identified all C–H bonds. The proton nuclear magnetic resonance (1H NMR) spectra in dry dimethyl sulfoxide allowed identification and assignment of the signals due to NH and OH protons. The derived structure, 3‐((1H‐indol‐3‐yl)methyl)‐3,3a,6‐trihydroxytetrahydrofuro[3,2‐b]furan‐2(5H)‐one, agrees with the structure suggested for ascorbigen A in 1966. The density functional theory (DFT) calculations showed that among 16 possible stereoisomers, only two complied with the almost zero value of the measured 3J(H6–H6a). Of the two stereoisomers, 3S,3aS,6S,6aR and 3R,3aR,6R,6aS, the latter was excluded on synthetic grounds. The nuclear Overhauser effect measurements unveiled close proximity between H2′ proton of the indole and the H6a proton of the tetrahydrofuro[3,2‐b]furan part. Detailed structural interpretation of the measured NMR parameters by means of DFT NMR was hampered by rotational flexibility of the indole and tetrahydrofuro[3,2‐b]furan parts and inadequacy of Polarizable Continuum Model (PCM) solvent model.
Pracoviště Ústav organické chemie a biochemie Kontakt asep@uochb.cas.cz ; Kateřina Šperková, Tel.: 232 002 584 ; Viktorie Chládková, Tel.: 232 002 434 Rok sběru 2020 Elektronická adresa https://onlinelibrary.wiley.com/doi/abs/10.1002/mrc.4890
Počet záznamů: 1