Article
Chemistry, Analytical
Daniel H. Lysak, William W. Wolff, Ronald Soong, Wolfgang Bermel, Eriks Kupce, Amy Jenne, Rajshree Ghosh Biswas, Daniel Lane, Genevieve Gasmi-Seabrook, Andre Simpson
Summary: Many important biological components contain nitrogen. However, N-15 nuclei are rarely used in NMR-based metabolite assignment due to their low abundance and the lack of comprehensive databases. In this study, a broadband N-15-edited H-1-C-13 HSQC NMR experiment was developed to identify nitrogen-containing metabolites based on their C-13, H-1, and N-15 chemical shifts.
ANALYTICAL CHEMISTRY
(2023)
Article
Energy & Fuels
Lina M. Yanez Jaramillo, Felix Link, Arno de Klerk
Summary: It is difficult to track compositional changes that affect the chemical nature of species during the conversion of high boiling oil fractions. Proton and carbon-13 nuclear magnetic resonance (H-1 and C-13 NMR) spectrometry can measure the aromatic hydrogen and aromatic carbon content in oils. There is only a rough correlation between aromatic carbon content and aromatic hydrogen content.
Article
Biotechnology & Applied Microbiology
Marynes Quintero, Lina M. Blandon, Oscar M. Vidal, Juan D. Guzman, Jorge E. Gomez-Marin, Albert D. Patino, Diego A. Molina, Gloria M. Puerto-Castro, Javier Gomez-Leon
Summary: This study evaluated the biological activity of extracts from marine bacteria cultures against Toxoplasma gondii and Mycobacterium tuberculosis. The Bacillus sp. INV FIR48 extract showed anti-T. gondii and anti-tuberculosis biological activity with low cytotoxicity, and peptide metabolites were detected in the extract. Marine bacteria are promising sources of natural products for anti-infective purposes, especially against prevalent diseases like toxoplasmosis and tuberculosis.
JOURNAL OF APPLIED MICROBIOLOGY
(2022)
Article
Chemistry, Organic
Aranya Das, Sk Ajarul, Sudipto Debnath, Poulami Hota, Dilip K. Maiti
Summary: This study demonstrates an unprecedented synthesis method using p-TsOH and MsOH as catalysts to construct valuable compounds. The metal-free Brönsted acid-mediated approach is operationally simple, highly regioselective, atom economical, high yielding, sustainable, and catalytically efficient.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Zhen Liu, Zi-Yang Qin, Ledong Zhu, Soumitra Athavale, Arkajyoti Sengupta, Zhi-Jun Jia, Marc Garcia-Borras, K. N. Houk, Frances H. Arnold
Summary: Propargyl amines are versatile synthetic intermediates with numerous applications in the pharmaceutical industry. An enzymatic platform for enantioselective propargylic amination of alkynes using a hydroxylamine derivative as the nitrene precursor was developed in this study. The biocatalytic process showed high efficiency and selectivity, making it a promising approach for industrial applications.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Fei Yu, Chuang Li, Chuangye Wang, Hongwei Zhang, Zhong-Yan Cao
Summary: A new, simple, and easily accessible (1-selenocyanatoethyl)-benzene has been developed and used as a SeCN group transfer reagent for selenocyanation of aliphatic C(sp(3))-H bonds for the first time. The protocol features mild reaction conditions and a wide substrate scope, with control experiments suggesting a radical-group transfer mechanism may be involved.
Article
Biochemistry & Molecular Biology
Yuriy Yu. Rusakov, Valentin A. Semenov, Irina L. Rusakova
Summary: The basis set issue is crucial for the accuracy of NMR chemical shift calculations. This paper presents the performance of the pecS-n (n = 1, 2) basis sets on a large dataset of H-1 and C-13 chemical shifts of 23 bioactive natural products. Alternative contraction schemes for the basis sets are proposed and evaluated. The study demonstrates that the contracted basis sets do not significantly improve the accuracy.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Organic
Alejandro Suarez-Lustres, Nuria Martinez-Yanez, Alvaro Velasco-Rubio, Jesus A. Varela, Carlos Saa
Summary: The first Pd-catalyzed [5 + 2] rollover annulation of 1-benzylpyrazoles with alkynes has been developed to assemble 10H-benzo[e]pyrazolo-[1,5-a]azepines (tricyclic 2-benzazepines). The rollover annulation involves twofold C-H activation of aryl and heteroaryl C-sp(2)-H bonds (C-H/C-H) of 1-benzylpyrazoles (five-atom partners) and alkynes, resulting in [5 + 2] annulated compounds.
Article
Plant Sciences
Estela Guerrero De Leon, Hugo Sanchez-Martinez, Juan A. Moran-Pinzon, Esther del Olmo Fernandez, Jose L. Lopez-Perez
Summary: In recent years, a significant number of natural products have been published with incorrectly assigned structures, despite having been previously correctly elucidated. The availability of databases containing revised structures can help prevent the spread of errors in structural elucidation. A dereplication tool called NAPROC-13, based on 13C chemical shift, has been used to identify substances that have been described with different structures but possess the same chemical shifts. Computational chemistry is employed to verify the correct structure among these proposed different structures. This paper presents the structural revision of nine triterpenoids using this methodology.
JOURNAL OF NATURAL PRODUCTS
(2023)
Article
Plant Sciences
Antoni Garcia-Baeza, Miguel Angel Alcalde, Olivier Grovel, Isaias Balderas-Renteria, Nemesio Villa-Ruano, Manuel Velazquez-Ponce, Elvia Becerra-Martinez, Karla Ramirez-Estrada
Summary: English Summary: Hairy root cultures of Centella asiatica can be used as bioproduction platforms to produce high-valuable metabolites. The application of methyl-jasmonate and coronatine in these cultures can cause significant changes in the metabolism of the plants. In this study, the metabolic responses of hairy roots to these molecules were analyzed using metabolomics approaches. The results showed that coronatine had a greater effect on reprogramming the metabolome compared to methyl-jasmonate. The activation of specialized pathways and the consumption of carbohydrates and amino acids were observed in coronatine-treated cultures. These findings provide valuable insights into the metabolic alterations caused by methyl-jasmonate and coronatine and the potential to manipulate the metabolism of C. asiatica hairy roots.
IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-PLANT
(2023)
Article
Chemistry, Organic
Khalid Boujdi, Nabil El Brahmi, Sylvain Collet, Didier Dubreuil, Monique Mathe-Allainmat, Mohamed Akssira, Gerald Guillaumet, Jacques Lebreton, Said El Kazzouli
Summary: A new solvent/ligand-controlled switchable C-H arylation of 1-methyl-4-nitro-1H-indazole catalyzed by Pd(OAc)(2) was achieved. Activation at the C7 position was promoted by a bidentate ligand in DMA, while arylation at the C3 position was directed by a phosphine ligand in H2O. The C3 and C7 arylation products were obtained in moderate to good yields and with high regioselectivity.
SYNTHESIS-STUTTGART
(2022)
Article
Chemistry, Applied
Zdenka Neuerova, Antonin Lycka
Summary: The one- and two-dimensional NMR spectra of benzenediazonium chloride coupling product with 4-R-naphthalene-1-ols were measured and analysed, revealing that the reaction products exist predominantly in hydrazone forms. Contrary to previous studies, it was found that more electron acceptor types of substituents actually cause an increase in hydrazone content in the compounds.
Article
Chemistry, Physical
Danhua Dai, Vasyl Denysenkov, Elena G. Bagryanskaya, Victor M. Tormyshev, Thomas F. Prisner, Andrei A. Kuzhelev
Summary: Dynamic nuclear polarization (DNP) is used to increase sensitivity in nuclear magnetic resonance (NMR), with recent advancements in high-field solid-effect DNP on H-1 nuclei in viscous liquids. This study expands the application of DNP in viscous media to C-13 nuclei. By combining solid-effect H-1 DNP with INEPT transfer, C-13 nuclei were successfully hyperpolarized using a triarylmethyl radical as a polarizing agent and glycerol-C-13(3) as an analyte, achieving enhancement factors of up to 45 at 9.4 T and room temperature.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Review
Chemistry, Multidisciplinary
Isabella C. Felli, Roberta Pierattelli
Summary: Modern C-13 NMR has become a valuable tool for biomolecular applications, allowing for complete protein assignment and unique information for the study of various biomolecules. Its different properties compared to H-1 provide the rationale for experiments and their applications in structural and dynamic characterization.
Article
Food Science & Technology
Maria Joao Cabrita, Arona Pires, Anthony J. Burke, Raquel Garcia
Summary: This study utilized 1D multinuclear NMR spectroscopy and multivariate statistical analysis to characterize olive oils from nine different varieties, with the model based on C-13 NMR DEPT 45 data showing stronger performance in discriminating olive oils based on their varietal origin. This suggests promising potential for using NMR-based spectroscopic tools in distinguishing olive oils of different varieties.
