The mass spectra of oxoquinolizidines

1970 ◽  
Vol 23 (4) ◽  
pp. 773 ◽  
Author(s):  
M Hussain ◽  
JS Robertson ◽  
TR Watson
Keyword(s):  
High Resolution ◽  
Mass Spectra ◽  
Deuterium Labelling ◽  
Initial Cleavage ◽  
Fragmentation Patterns

The mass spectra of quinolizidine and of 1-, 2-, and 3-oxoquinolizidine have been determined. The suggested fragmentation patterns are supported by high resolution measurements and deuterium labelling. It would appear that the fragmentation patterns are mainly influenced by the nitrogen; the initial cleavage occurs in the C-C bond which is α with respect to the nitrogen.

The mass spectra of acridones

1967 ◽  
Vol 20 (6) ◽  
pp. 1179 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
RH Prager ◽  
HM Thredgold
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Structure Determination ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Skeletal Rearrangement ◽  
Deuterium Labelling ◽  
Naturally Occurring ◽  
Fragmentation Patterns

The mass spectra of 34 acridones have been determined and interpreted with the aid of both high-resolution measurements and deuterium labelling studies. The spectra contain pronounced molecular ions and are free of skeletal rearrangement fragments. The fragmentation patterns are dependent on the nature and position of substituents, and therefore mass spectrometry can be a useful aid to structure determination in this class of naturally occurring compounds.

scholarly journals Benzodiazepine Analogues. Part 20. Mass Spectrometric Analysis of Benzoxathiepine Derivatives

1999 ◽  
Vol 23 (9) ◽  
pp. 584-585
Author(s):  
Aifheli C. Gelebe ◽  
Perry T. Kaye
Keyword(s):  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
Mass Spectrometric Analysis ◽  
Spectrometric Analysis ◽  
Low Resolution ◽  
Fragmentation Patterns ◽  
Resolution Mass

Fragmentation patterns in the electron-impact (El) mass spectra of benzoxathiepine derivatives are elucidated using a combination of high-resolution and comparative low-resolution mass spectrometric analysis.

Mass spectra of 1,2,4-Rriazoles. I. Methyl- and Phenyl-1,2,4-triazoline-5-thiones

1972 ◽  
Vol 25 (2) ◽  
pp. 335 ◽  
Author(s):  
AJ Blackman ◽  
JH Bowie
Keyword(s):  
High Resolution ◽  
Mass Spectra ◽  
Fragmentation Patterns ◽  
Derivatives Of

The mass spectra of the monomethyl and monophenyl derivatives of 1,2,4-triazoline-5-thione are reported and discussed. The fragmentation patterns of these compounds are complex, and the investigation was aided by 2H, 15N, and 15N-2H labelling, metastable defocusing, and high-resolution studies.

Diazabenzenes. II. Synthesis, Photolysis and Mass Spectra of Some Tetraalkylpyrazines

1979 ◽  
Vol 32 (6) ◽  
pp. 1281 ◽  
Author(s):  
DJ Bell ◽  
IR Brown ◽  
R Cocks ◽  
RF Evans ◽  
GA Macfarlane ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
High Resolution ◽  
Sodium Borohydride ◽  
Mass Spectra ◽  
Ammonium Acetate ◽  
Zinc Dust ◽  
Deuterium Labelling ◽  
Complete Reduction ◽  
Pyrazine Ring ◽  
Resolution Mass

2,3,5,6-Tetramethyl-, tetraethyl- and tetraisopropyl-pyrazines were obtained by fusion of ammonium acetate with the appropriate acyloin or reduction of the α,α'-diketone dioxime with zinc dust and alkali. Photolysis of a cyclohexane solution of tetraisopropylpyrazine led inter alia to formation of bicyclohexyl. Photolysis of an aqueous solution of tetramethylpyrazine containing sodium borohydride caused complete reduction of the pyrazine ring to the hexahydro stage. The high-resolution mass spectra of these pyrazines are discussed and explained in the light of deuterium labelling and metastable defocusing information.

Electron impact studies. XVIII. Mass spectra of pyridazines, phthalazines, and related compounds

1967 ◽  
Vol 20 (12) ◽  
pp. 2677 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
PF Donaghue ◽  
JA Halleday ◽  
HJ Rodda
Keyword(s):  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Prominent Feature ◽  
Substitution Pattern ◽  
Impact Studies ◽  
Metastable Ions ◽  
Fragmentation Patterns ◽  
Related Compounds

The mass spectra of substituted pyridazines, phthalazines, and related compounds are reported and discussed. Molecular ions are a prominent feature of all the spectra, and fragmentation modes may be usefully correlated with both the type of heterocycle and its substitution pattern. Fragmentation patterns have been substantiated by extensive high resolution studies and appropriate metastable ions.

scholarly journals AHLF: ad hoc learning of fragmentation patterns in mass spectra detects post-translationally modified peptides prior to database search

2020 ◽  
Author(s):  
Tom Altenburg ◽  
Shengbo Wang ◽  
Thilo Muth ◽  
Bernhard Y. Renard
Keyword(s):  
Deep Learning ◽  
Mass Spectrum ◽  
High Resolution ◽  
Mass Spectra ◽  
Ad Hoc ◽  
Data Driven ◽  
High Resolution Spectrum ◽  
Tandem Mass ◽  
End To End ◽  
Fragmentation Patterns

AbstractMotivationPublicly available mass spectrometry-based proteomics data has grown exponentially in the recent past. Yet, large scale spectrum-centered analysis usually involves predefined fragmentation features that are limited and prone to be biased. Using deep learning, the decision making for a suitable fragmentation model can be carried out in a data-driven manner.ResultsWe introduce a framework that allows end-to-end training of generic deep learning models on a large collection of high resolution tandem mass spectra. In this case we used 19.2 million labeled spectra from more than a hundred individual PRIDE repositories. In our framework, we developed a representation that captures the complete information of a high-resolution spectrum facilitating a loss-less reduction of the number of features largely independent of the actual resolution. Additionally, it allows us to use common trainable layers, e.g. recurrent or convolutional operations. Specifically, we use a deep network of stacked dilated convolutions to model long range associations between any peaks within a tandem mass spectrum. We exemplify our approach by learning to detect post-translational modifications – in this case, protein phosphorylation – only based on a given mass spectrum in a fully data-driven manner. To the best of our knowledge, this is the first end-to-end trained deep learning model on tandem spectra that is able to ad hoc learn fragmentation patterns in high-resolution spectra. Our approach outperforms the current state-of-the-art in predicting if a mass spectrum originates from a phosphorylated peptide.AvailabilityOur deep learning framework is implemented in tensorflow. The open source code including trained weights is available at gitlab.com/dacs-hpi/[email protected]

Mass spectra of α-diketones. I. Non-enolized α-diketones

1968 ◽  
Vol 21 (5) ◽  
pp. 1247 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
GE Gream ◽  
MH Laffer
Keyword(s):  
Mass Spectra ◽  
Molecular Ions ◽  
Ring Size ◽  
Mass Measurements ◽  
Exact Mass ◽  
Deuterium Labelling ◽  
Mclafferty Rearrangement ◽  
Metastable Ions ◽  
Fragmentation Patterns

The mass spectra of a series of a-diketones are reported and discussed. Fragmentation patterns have been substantiated by exact mass measurements, metastable ions, and in two cases, by deuterium labelling studies. The McLafferty rearrangement is not observed in the spectra of aliphatic α-diketones; fragmentation proceeds by α-cleavage. The fragmentation modes of those cyclic α-diketones studied depend largely on the ring size. Molecular ions are observed in all spectra.

Exploring the Active Compounds of Traditional Mongolian Medicine Agsirga in Intervention of Novel Coronavirus (2019-nCoV) Based on HPLC-Q-Exactive-MS/MS and Molecular Docking Method

2020 ◽  
Author(s):  
Jie Cheng ◽  
Yuchen Tang ◽  
Baoquan Bao ◽  
Ping Zhang
Keyword(s):  
Mass Spectrometry ◽  
Molecular Docking ◽  
High Resolution ◽  
Mass Spectra ◽  
High Resolution Mass Spectrometry ◽  
Structural Formula ◽  
Active Compounds ◽  
High Resolution Mass ◽  
Q Exactive ◽  
Resolution Mass

<p><a></a><a></a><a></a><a><b>Objective</b></a>: To screen all compounds of Agsirga based on the HPLC-Q-Exactive high-resolution mass spectrometry and find potential inhibitors that can respond to 2019-nCoV from active compounds of Agsirga by molecular docking technology.</p> <p><b>Methods</b>: HPLC-Q-Exactive high-resolution mass spectrometry was adopted to identify the complex components of Mongolian medicine Agsirga, and separated by the high-resolution mass spectrometry Q-Exactive detector. Then the Orbitrap detector was used in tandem high-resolution mass spectrometry, and the related molecular and structural formula were found by using the chemsipider database and related literature, combined with precise molecular formulas (errors ≤ 5 × 10<sup>−6</sup>) , retention time, primary mass spectra, and secondary mass spectra information, The fragmentation regularities of mass spectra of these compounds were deduced. Taking ACE2 as the receptor and deduced compounds as the ligand, all of them were pretreated by discover studio, autodock and Chem3D. The molecular docking between the active ingredients and the target protein was studied by using AutoDock molecular docking software. The interaction between ligand and receptor is applied to provide a choice for screening anti-2019-nCoV drugs.</p> <p><b>Result</b>: Based on the fragmentation patterns of the reference compounds and consulting literature, a total of 96 major alkaloids and stilbenes were screened and identified in Agsirga by the HPLC-Q-Exactive-MS/MS method. Combining with molecular docking, a conclusion was got that there are potential active substances in Mongolian medicine Agsirga which can block the binding of ACE2 and 2019-nCoV at the molecular level.</p>

Mass Spectra of β-Keto Esters

1972 ◽  
Vol 50 (16) ◽  
pp. 2707-2710 ◽  
Author(s):  
Larry Weiler
Keyword(s):  
Mass Spectra ◽  
Carbonyl Groups ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Keto Esters ◽  
Fragmentation Patterns

The mass spectra of several γ-substituted β-keto esters have been recorded and interpreted. The fragmentation patterns are compared to those of α-substituted β-keto esters and are found to be very useful in differentiating the α- and γ-substituted isomers. The mass spectral fragmentation schemes are dominated by cleavages α to the carbonyl groups and by McLafferty rearrangements.

Sign in / Sign up

Export Citation Format

Share Document