Synthesis and 1H NMR data assignment of 3-acetamido-4-amino-3,4-dihydro-2H-pyran-6-carboxylates and their acetyl-migrated isomers

2021 ◽  
pp. 1-9
Author(s):  
Chuanqi Duan ◽  
Weiyuan Liu ◽  
Liang Chen ◽  
Jing Pan ◽  
Yubin Liu ◽  
...  
Keyword(s):  
1H Nmr ◽  
Nmr Data

Unexpected Keto-enol Tautomerism in the Cyclopyridinophane Class Direct and indirect proofs

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
Paul Ionut Dron ◽  
Neculai Doru Miron ◽  
Gheorghe Surpateanu
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Stable Conformer ◽  
Ph Measurements ◽  
Theoretical Methods ◽  
Nmr Data ◽  
Tautomeric Forms ◽  
New Compounds

The paper presents the synthesis of cyclo (bis-paraquat p-phenylene p-phenylene-carbonyl) tetrakis (hexafluorophosphate), named �CETOBOX�, and the closely related structural determinations. This compound exists in three tautomeric forms. These forms were evidentiated by NMR-data (1H-NMR, TOCSY, COSY, NOESY), UV-Vis spectra coupled with pH measurements and by synthesis. As the �CETOBOX� gives �in situ� only the corresponding monoylide, the synthesis of a new fluorescent indolizine cyclophane has been performed by a 3+2 cycloaddition. All structures of the new compounds presented herein have been established by NMR spectroscopy. Also, theoretical methods (MM3, AM1, AM1-COSMO and B88LYPDFT) have been used to determine the most stable conformer structures.

scholarly journals DP4-AI Automated NMR Data Analysis: Straight from Spectrometer to Structure

2020 ◽  
Author(s):  
Alexander Howarth ◽  
Kristaps Ermanis ◽  
Jonathan Goodman
Keyword(s):  
1H Nmr ◽  
Open Source Software ◽  
Processing Speed ◽  
Structure Elucidation ◽  
Structural Information ◽  
Fold Increase ◽  
Structural Uncertainty ◽  
Large Sets ◽  
Nmr Data ◽  
Objective Model

<div> <p>A robust system for automatic processing and assignment of raw 13C and 1H NMR data DP4-AI has been developed and integrated into our computational organic molecule structure elucidation workflow. Starting from a molecular structure with undefined stereochemistry or other structural uncertainty, this system allows for completely automated structure elucidation. Methods for NMR peak picking using objective model selection and algorithms for matching the calculated 13C and 1H NMR shifts to peaks in noisy experimental NMR data were developed. DP4-AI achieved a 60-fold increase in processing speed, and near-elimination of the need for scientist time, when rigorously evaluated used a challenging test set of molecules. DP4-AI represents a leap forward in NMR structure elucidation and a step-change in the functionality of DP4. It enables high-throughput analyses of databases and large sets of molecules, which were previously impossible, and paves the way for the discovery of new structural information through machine learning. This new functionality has been coupled with an intuitive GUI and is available as open-source software at https://github.com/KristapsE/DP4-AI.</p> </div> <br>

scholarly journals Water soluble metal-polymeric complexes of gallium and triple co-polymer of N-vinylpyrrolidone with N-vinylformamide and N-vinylminodiacetic acid

2019 ◽  
Vol 485 (3) ◽  
pp. 306-310
Author(s):  
N. I. Gorshkov ◽  
A. Yu. Murko ◽  
I. I. Gavrilova ◽  
I. I. Malakhova ◽  
V. D. Krasikov ◽  
...  
Keyword(s):  
Molecular Weight ◽  
1H Nmr ◽  
Metal Ion ◽  
Water Soluble ◽  
Polymer Complex ◽  
Nmr Data ◽  
Exclusion Chromatography ◽  
Polymeric Complexes ◽  
Metal Polymer

A terpolymer with a molecular weight of 45 kDa containing 7 mol.% of vinylamine units, 80 mol.% of vinylpyrrolidone, and 3 mol.% of vinyliminodiacetic acid units has been synthesized. Its complexation with Ga3+ ion has been studied by HPLC. The resulting metal–polymer complex has been characterized by exclusion chromatography and spectral (IR, 1H NMR) data. The complex has a monomolecular structure where the metal ion acts as an anchor fragment between vinyliminodiacetic acid units and is stable in the reaction of interligand exchange with histidine.

Preparation of Cellulose Stearate and Cellulose Acetate Stearate in 1-Butyl-3-Methylimidazolium Chloride

2013 ◽  
Vol 559 ◽  
pp. 105-110 ◽  
Author(s):  
Elvira Tarasova ◽  
Dmitri Šumigin ◽  
M. Kudrjašova ◽  
A. Krumme
Keyword(s):  
Ionic Liquid ◽  
Cellulose Acetate ◽  
1H Nmr ◽  
Hydroxyl Group ◽  
Cellulose Esters ◽  
Nmr Data

Cellulose stearates were prepared in a 1-butyl-3-metylimidazolium chloride ionic liquid. The addition of base pyridine as well as catalyst Tin octoate sufficiently increases the degree of hydroxyl group substitution. The new path for preparation of cellulose mixed esters, namely cellulose acetate stearate (CAS), is performed. The 1H NMR data confirmed the structure of obtained mono- and mix- cellulose esters.

Application of support vector machines to 1H NMR data of fish oils: methodology for the confirmation of wild and farmed salmon and their origins

2007 ◽  
Vol 387 (4) ◽  
pp. 1499-1510 ◽  
Author(s):  
Saeed Masoum ◽  
Christophe Malabat ◽  
Mehdi Jalali-Heravi ◽  
Claude Guillou ◽  
Serge Rezzi ◽  
...  
Keyword(s):  
Support Vector Machines ◽  
1H Nmr ◽  
Fish Oils ◽  
Support Vector ◽  
Farmed Salmon ◽  
Nmr Data ◽  
Vector Machines

scholarly journals Comparative Metabolite Profiling of Wild and Cultivated Justicia procumbens L. Based on 1H-NMR Spectroscopy and HPLC-DAD Analysis

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 860
Author(s):  
Hyunyong Lee ◽  
Jihyun Jeon ◽  
Joobyoung Yoon ◽  
Seung-Hwan Kim ◽  
Hyun Sik Choi ◽  
...  
Keyword(s):  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Raw Material ◽  
Cultivated Plants ◽  
Phase I Clinical Trials ◽  
Marker Compound ◽  
Nmr Data ◽  
Asthma Drug ◽  
Phytochemical Constituents ◽  
First Time

Justicia procumbens L. is known across Korea, India, China, and Taiwan as a remedy against fever, cough, sore throat, and cirrhosis of ascites. J. procumbens provides the raw material for a candidate anti-asthma drug (DW2008S) currently completing phase I clinical trials sponsored by Dong Wha Pharmaceutical Company. HPLC-DAD was used to quantify phytochemical constituents of J. procumbens, and HPLC and 1H-NMR results were assessed by multivariate analysis. This is the first time a comparative study using HPLC-DAD and NMR fingerprints has been applied to identify chemical differences between wild and cultivated J. procumbens. The amount of justicidin B as the marker compound was higher in cultivated samples (0.80 ± 0.25 mg/g) than in wild ones (0.63 ± 0.30 mg/g). Orthogonal partial least squares discriminant analysis (OPLS-DA) from HPLC and NMR data revealed that there were clear differences between wild and cultivated types and identified five secondary metabolites, which could help distinguish between wild and cultivated plants. Among these five lignans, diphyllin showed the most potent discrimination between two types and was significantly detected higher in cultivated ones than in wild ones. A combination of 1H-NMR and HPLC-DAD analysis is effective for J. procumbens standardization and metabolomics studies.

Characterization of the measurement error structure in 1D 1H NMR data for metabolomics studies

2009 ◽  
Vol 636 (2) ◽  
pp. 163-174 ◽  
Author(s):  
Tobias K. Karakach ◽  
Peter D. Wentzell ◽  
John A. Walter
Keyword(s):  
Measurement Error ◽  
1H Nmr ◽  
Error Structure ◽  
Nmr Data
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