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.

Electron impact studies. XII. Mass spectra of substituted imidazoles

1967 ◽  
Vol 20 (8) ◽  
pp. 1613 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
S Lawesson ◽  
G Schroll
Keyword(s):  
Mass Spectrometry ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Skeletal Rearrangement ◽  
Mass Measurements ◽  
Exact Mass ◽  
Metastable Ions ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns

The mass spectra of 37 imidazoles are reported and discussed. The spectra exhibit pronounced molecular ions and characteristic fragmentation patterns. The fragmentation modes have been substantiated by deuterium labelling, exact mass measurements, and appropriate metastable ions. Skeletal rearrangement fragments are rare in these spectra; consequently mass spectrometry is useful for structure elucidation of imidazoles.

Mass Spectrometry: The Elimination of CO from Substituted Nitro Naphthalenes

1966 ◽  
Vol 21 (3) ◽  
pp. 210-213 ◽  
Author(s):  
J. H. Beynon ◽  
B. E. Job ◽  
A. E. Williams
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Electron Density ◽  
Mass Spectra ◽  
Molecular Ions

The mass spectra of 1-nitronaphthalene, 2-nitronaphthalene and eight substituted nitro naphthalenes have been studied. The loss of neutral CO from the molecular ions of these compounds has been established by high resolution techniques and study of “meta stable” peaks. The probability of elimination has been related to the electron density at the 8-position.

Electron impact studies. XXXI. Skeletal-rearrangement fragments in the mass spectra of anils

1968 ◽  
Vol 21 (8) ◽  
pp. 2021 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
JW Fisher ◽  
T McL Spotswood
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
General Type ◽  
High Resolution Mass Spectrometry ◽  
Aromatic Aldehydes ◽  
Skeletal Rearrangement ◽  
Rearrangement Processes ◽  
Resolution Mass

Skeletal-rearrangement fragments are observed in the mass spectra of all anils derived from aromatic aldehydes. The rearrangement processes have been studied by high-resolution mass spectrometry and in certain cases by deuterium labelling. All processes are of the general type [ABC]+ → [AC]+ +B.

Gas-Phase Chemistry of the Negative Ions of Fully-Protected Peptides by High-Resolution Electrospray Ionization Tandem Mass Spectrometry

2005 ◽  
Vol 11 (4) ◽  
pp. 403-408 ◽  
Author(s):  
Anna Napoli ◽  
Leonardo Di Donna ◽  
Giovanni Sindona ◽  
Elena Urso
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Tandem Mass Spectrometry ◽  
Mass Spectra ◽  
Negative Ions ◽  
Structural Data ◽  
Molecular Ions ◽  
Low Energy ◽  
Tandem Mass ◽  
Esi Ms

Fully-protected C-terminal free peptides can be conveniently analyzed by high-resolution electrospray tandem mass spectrometry (ESI-MS/MS) in a quadrupole quadrupole time-of-flight tandem hybrid mass spectrometer, operated in the negative (–) ionization mode. The unusual choice of negative ions in mass spectrometry applications to peptide analysis was needed to obtain exhaustive sequence and structural data. The low-energy collision-induced dissociation (CID) experiments provided, in fact, tandem mass spectra displaying highly diagnostic fragments with a good signal-to-noise ratio. The method is applied to segments of porcine calcitonin (Cal), Cal (10–16, 1), Cal (17–24, 2) and Cal (25–28, 3) whose [M–H]− deprotonated molecular ions provided low-energy CID mass spectra which allow the evaluation either of the primary structure of the peptide and of the location of the side-chain protective groups. ESI (+) MS can be conveniently used, in the high resolution mode, to achieve precise information on the elemental composition of the examined peptides.

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.

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.

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>

Electron impact studies. VI. Mass spectra of esters and thioesters. Skeletal rearrangement on electron impact

1967 ◽  
Vol 20 (4) ◽  
pp. 689 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
P Jakobsen ◽  
S Lawesson ◽  
G Schroll
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
Skeletal Rearrangement ◽  
Unsaturated Esters ◽  
Impact Studies ◽  
Unsaturated Alcohols ◽  
Metastable Ions

The mass spectra of representative series of simple alkyl acetoacetates, alkyl acetothioacetates, and some unsaturated esters derived from unsaturated alcohols or phenols are reported and discussed. The fragmentation schemes have been established by high resolution measurements, appropriate metastable ions, and by deuterium and 18O labelling. Many of the spectra show significant skeletal rearrangement fragments arising from either loss of carbon monoxide or carbon dioxide.

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