Prediction of carbon-13 nuclear magnetic resonance chemical shifts by artificial neural networks

1992 ◽  
Vol 64 (10) ◽  
pp. 1157-1164 ◽  
Author(s):  
Lawrence S. Anker ◽  
Peter C. Jurs
Keyword(s):  
Neural Networks ◽  
Nuclear Magnetic Resonance ◽  
Artificial Neural Networks ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Artificial Neural ◽  
Nuclear Magnetic

scholarly journals Predicting Chemical Shifts with Graph Neural Networks

2021 ◽  
Author(s):  
Ziyue Yang ◽  
Maghesree Chakraborty ◽  
Andrew D White
Keyword(s):  
Molecular Structure ◽  
Neural Networks ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
3D Structure ◽  
Forward Model ◽  
Forward Models ◽  
Graph Neural Networks ◽  
Nuclear Magnetic

Inferring molecular structure from Nuclear Magnetic Resonance (NMR) measurements requires an accurate forward model that can predict chemical shifts from 3D structure. Current forward models are limited to specific molecules...

scholarly journals Cryptococcus neoformans Chemotyping by Quantitative Analysis of 1H Nuclear Magnetic Resonance Spectra of Glucuronoxylomannans with a Computer-Simulated Artificial Neural Network

1998 ◽  
Vol 5 (2) ◽  
pp. 146-159 ◽  
Author(s):  
Robert Cherniak ◽  
Homayoun Valafar ◽  
Laura C. Morris ◽  
Faramarz Valafar
Keyword(s):  
Neural Network ◽  
Nuclear Magnetic Resonance ◽  
Artificial Neural Network ◽  
Magnetic Resonance ◽  
Cryptococcus Neoformans ◽  
Chemical Shifts ◽  
Proton Nmr ◽  
Relative Distribution ◽  
Artificial Neural ◽  
Nuclear Magnetic

ABSTRACT The complete assignment of the proton chemical shifts obtained by nuclear magnetic resonance (NMR) spectroscopy of de-O-acetylated glucuronoxylomannans (GXMs) from Cryptococcus neoformanspermitted the high-resolution determination of the total structure of any GXM. Six structural motifs based on an α-(1→3)-mannotriose substituted with variable quantities of 2-O-β- and 4-O-β-xylopyranosyl and 2-O-β-glucopyranosyluronic acid were identified. The chemical shifts of only the anomeric protons of the mannosyl residues served as structure reporter groups (SRG) for the identification and quantitation of the six triads present in any GXM. The assigned protons for the mannosyl residues resonated at clearly distinguishable positions in the spectrum and supplied all the information essential for the assignment of the complete GXM structure. This technique for assigning structure is referred to as the SRG concept. The SRG concept was used to analyze the distribution of the six mannosyl triads of GXMs obtained from 106 isolates of C. neoformans. The six mannosyl triads occurred singularly or in combination with one or more of the other triads. The identification and quantitation of the SRG were simplified by using a computer-simulated artificial neural network (ANN) to automatically analyze the SRG region of the one-dimensional proton NMR spectra. The occurrence and relative distribution of the six mannosyl triads were used to chemotype C. neoformans on the basis of subtle variations in GXM structure determined by analysis of the SRG region of the proton NMR spectrum by the ANN. The data for the distribution of the six SRGs from GXMs of 106 isolates of C. neoformansyielded eight chemotypes, Chem1 through Chem8.

Carbon-13 nuclear magnetic resonance examination of naphthalene derivatives. Assignments and analysis of substituent chemical shifts

1977 ◽  
Vol 42 (14) ◽  
pp. 2411-2418 ◽  
Author(s):  
William Kitching ◽  
Maxwell Bullpitt ◽  
David Gartshore ◽  
William Adcock ◽  
T. C. Khor ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Magnetic Resonance Examination ◽  
Naphthalene Derivatives ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance Chemical Shifts of some Monosubstituted Isothiazoles

1975 ◽  
Vol 53 (4) ◽  
pp. 596-603 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Thomas R. Clem ◽  
Edwin D. Becker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Charge Densities ◽  
Monosubstituted Benzenes ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

Carbon-13 and proton chemical shifts have been measured for several monosubstituted isothiazoles. Substituent effects upon these chemical shifts are compared with those observed for monosubstituted benzenes, pyridines, and thiophenes. In general the observed substituent effects in the isothiazoles and thiophenes closely parallel one another. Correlations between the observed carbon-13 Chemical shifts and CNDO/2 calculated charge densities are examined.

Studies of specifically fluorinated carbohydrates. Part I. Nuclear magnetic resonance studies of hexopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 1-17 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville ◽  
N. S. Bhacca
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Angular Dependence ◽  
Chemical Shifts ◽  
Relative Orientation ◽  
Coupling Constants ◽  
Pyranose Ring ◽  
Spectral Parameters ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

A detailed study has been made of both the 1H and 19F nuclear magnetic resonance (n.m.r.) spectra of a series of hexopyranosyl fluoride derivatives. Some of the 1H spectra were measured at 220 MHz. The 1H spectral parameters define both the configuration and the conformation of each of these derivatives. Study of the 19F n.m.r. parameters revealed several stereospecific dependencies. The 19F chemical shifts depend upon, (a) the orientation of the fluorine substituent with respect to the pyranose ring and, (b) the relative orientation of other substituents attached to the ring; for acetoxy substituents, these configurational dependencies appear to be additive. The vicinal19F–1H coupling constants exhibit a marked angular dependence for which Jtrans = ca. 24 Hz whilst Jgauche = 1.0 to 1.5 Hz for [Formula: see text] and 7.5 to 12.6 Hz for [Formula: see text] The geminal19F–1H couplings depend on the orientation of the substituent at C-2; when this substituent is equatorial JF,H is ca. 53.5 Hz and when it is axial the value is ca. 49 Hz.

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