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Computational 1 H and 13 C NMR of the trimeric monoterpenoid indole alkaloid strychnohexamine: Selected spectral updates
Author(s) -
Semenov Valentin A.,
Krivdin Leonid B.
Publication year - 2021
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.5129
Subject(s) - chemistry , chemical shift , nmr spectra database , carbon 13 nmr , proton , indole test , spectral line , indole alkaloid , resonance (particle physics) , nuclear magnetic resonance spectroscopy , carbon 13 , carbon 13 nmr satellite , stereochemistry , proton nmr , crystallography , fluorine 19 nmr , physics , atomic physics , quantum mechanics , astronomy
Very large trimeric indole alkaloid strychnohexamine, with empirical formula C 59 H 60 N 6 O (66 second‐row atoms and 60 protons), has been subjected to the state‐of‐the‐art computation of the 1 H and 13 C nuclear magnetic resonance (NMR) chemical shifts of its configurational isomers at each of the 14 asymmetric centers. Several spectral reassignments and corrections of 1 H and 13 C NMR spectra of this alkaloid were suggested based on the PBE0/pcSseg‐2//pcseg‐2 calculation of its NMR chemical shifts. Thus, all pairs of diastereotopic protons were assigned together with four aromatic carbon resonances of C‐9 and C‐11, C‐9″, and C‐11″. In addition, the unassigned chemical shifts of carbon C‐23″ and proton at C‐3′ in, accordingly, 13 C and 1 H NMR spectra were predicted.