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Authors: Mary P. Choules ORCID , Jonathan Bisson ORCID , Wei Gao , David C. Lankin ORCID , James B. McAlpine ORCID , Matthias Niemitz ORCID , Birgit U. Jaki ORCID , Scott G. Franzblau ORCID , Guido F. Pauli ORCID
Journal: Journal of Organic Chemistry (RoMEO status: White)
Subjects:
NMR
Ensuring identity, purity, and reproducibility are equally essential during synthetic chemistry, drug discovery, and for pharmaceutical product safety. Many peptidic APIs are large molecules that require considerable effort for integrity assurance. This study builds on quantum mechanical 1H iterative Full Spin Analysis (HiFSA) to establish NMR peptide sequencing methodology that overcomes the intrinsic limitations of principal compendial methods in identifying small structural changes or minor impurities that affect effectiveness and safety.
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categories publications science
Authors: Guido F. Pauli ORCID , Matthias Niemitz ORCID , Jonathan Bisson ORCID , Michael W. Lodewyk , Cristian Soldi , Jared T. Shaw , Dean J. Tantillo ORCID , Jordy M. Saya , Klaas Vos , Roel A. Kleinnijenhuis , Henk Hiemstra , Shao-Nong Chen ORCID , James McAlpine , David C. Lankin ORCID , J. Brent Friesen ORCID
Journal: Journal of Organic Chemistry (RoMEO status: White)
Subjects:
NMR
FID
The revision of the structure of the sesquiterpene aquatolide from a bicyclo[2.2.0]hexane to a bicyclo[2.1.1]hexane structure using compelling NMR data, X-ray crystallography, and the recent confirmation via full synthesis exemplify that the achievement of “structural correctness” depends on the completeness of the experimental evidence. Archived FIDs and newly acquired aquatolide spectra demonstrate that archiving and rigorous interpretation of 1D 1H NMR data may enhance the reproducibility of (bio)chemical research and curb the growing trend of structural misassignments.
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categories publications science
Authors: Joo-Won Nam ORCID , Rasika Phansalkar , David C. Lankin ORCID , Jonathan Bisson ORCID , James McAlpine , Ariene A. Leme , Cristina M.P. Vidal , Benjamin Ramirez , Matthias Niemitz ORCID , Ana Bedran-Russo , Shao-Nong Chen ORCID , Guido F. Pauli ORCID
Journal: Journal of Organic Chemistry (RoMEO status: White)
Subjects:
NMR
The ability of certain oligomeric proanthocyanidins (OPACs) to enhance the biomechanical properties of dentin involves collagen cross-linking of the 1.3–4.5 nm wide space via protein–polyphenol interactions. A systematic interdisciplinary search for the bioactive principles of pine bark has yielded the trimeric PAC, ent-epicatechin-(4β→8)-epicatechin-(2β→O→7,4β→8)-catechin (3), representing the hitherto most potent single chemical entity capable of enhancing dentin stiffness. Building the case from two congeneric PAC dimers, a detailed structural analysis decoded the stereochemistry, spatial arrangement, and chemical properties of three dentin biomodifiers.
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categories publications science