The synthesis and mass spectra of some oxygen-bridged 5α-cholestane and B-homo-5α-cholestane derivatives

1980 ◽  
Vol 45 (1) ◽  
pp. 274-293 ◽  
Author(s):  
František Tureček ◽  
Pavel Kočovský
Keyword(s):  
Mass Spectra ◽  
Mass Spectrometric ◽  
Oxygen Bridge ◽  
Fragmentation Patterns ◽  
Steroid Skeleton ◽  
Bridge Position

The synthesis and mass spectrometric behaviour of a series of oxygen-bridged α-cholestans and B-homo-5α-cholestans I-X are described. The differences in fragmentation patterns of these compounds are discussed in dependence on the position of the oxygen bridge, position and configuration of additional substituents and conformation of the A and B rings of the steroid skeleton.

Mass spectra of some 5-methyl-19-nor-5β-cholest-9-enes

1979 ◽  
Vol 44 (2) ◽  
pp. 429-438 ◽  
Author(s):  
František Tureček ◽  
Pavel Kočovský
Keyword(s):  
Mass Spectra ◽  
Mass Spectrometric ◽  
Fragmentation Patterns ◽  
Mass Spectrometric Behavior

The mass spectrometric behavior of isomeric ketones I-V and alcohols VI-X of Westphalen type is described. The differences in fragmentation patterns of these compounds are discussed in dependence on the position and the configuration of the substituent.

scholarly journals Rapid Mass Spectrometric Analysis of a Novel Fucoidan, Extracted from the Brown AlgaCoccophora langsdorfii

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Stanislav D. Anastyuk ◽  
Tatyana I. Imbs ◽  
Pavel S. Dmitrenok ◽  
Tatyana N. Zvyagintseva
Keyword(s):  
Mass Spectra ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Low Molecular Weight ◽  
Ionization Mass ◽  
The Novel ◽  
Fragmentation Patterns ◽  
Rapid Mass

The novel highly sulfated (35%) fucoidan fractionCf2, which contained, along with fucose, galactose and traces of xylose and uronic acids was purified from the brown algaCoccophora langsdorfii. Its structural features were predominantly determined (in comparison with fragments of known structure) by a rapid mass spectrometric investigation of the low-molecular-weight fragments, obtained by “mild” (5 mg/mL) and “exhaustive” (maximal concentration) autohydrolysis. Tandem matrix-assisted laser desorption/ionization mass spectra (MALDI-TOF/TOFMS) of fucooligosaccharides with even degree of polymerization (DP), obtained by “mild” autohydrolysis, were the same as that observed for fucoidan fromFucus evanescens, which have a backbone of alternating (1 → 3)- and (1 → 4) linked sulfated at C-2 and sometimes at C-4 of 3-linkedα-L-Fucpresidues. Fragmentation patterns of oligosaccharides with odd DP indicated sulfation at C-2 and at C-4 of (1 → 3) linkedα-L-Fucpresidues on the reducing terminus. Minor sulfation at C-3 was also suggested. The “exhaustive” autohydrolysis allowed us to observe the “mixed” oligosaccharides, built up of fucose/xylose and fucose/galactose. Xylose residues were found to occupy both the reducing and nonreducing termini of FucXyl disaccharides. Nonreducing galactose residues as part of GalFuc disaccharides were found to be linked, possibly, by 2-type of linkage to fucose residues and were found to be sulfated, most likely, at position C-2.

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 spectrometry of ozonides

1969 ◽  
Vol 47 (6) ◽  
pp. 919-934 ◽  
Author(s):  
J. Castonguay ◽  
M. Bertrand ◽  
J. Carles ◽  
S. Fliszár ◽  
Y. Rousseau
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
Fragment Ions ◽  
Spectrometric Identification ◽  
Mass Spectrometric Identification ◽  
Fragmentation Patterns

The mass spectra of some ozonides are reported, and the modes of formation of the major fragment ions tentatively described. The use of 18O-labelled compounds has proven to be useful in establishing fragmentation patterns. It is concluded that these follow a characteristic path, which is common to all the ozonides studied and permits mass spectrometric identification.

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.

scholarly journals Mass Spectrometric Studies on Organic Selenium-Oxygen Compounds. 2. Mass Spectra of Diphenyl Selenoxide and 4,4'-Dimethyl-diphenyl Selenoxide.

1970 ◽  
Vol 24 ◽  
pp. 717-719 ◽  
Author(s):  
Erik Rebane ◽  
Kjell-Ivar Dahlqvist ◽  
Sture Forsén ◽  
Ulf Ragnarsson ◽  
S. E. Rasmussen ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Mass Spectrometric ◽  
Organic Selenium

scholarly journals Mass Spectrometric Studies on Organic Selenium-Oxygen Compounds. 1. Mass Spectra of Methyl p-Chlorobenzene Selenonate and Methyl p-Bromobenzene Selenonate.

1969 ◽  
Vol 23 ◽  
pp. 1817-1819 ◽  
Author(s):  
Erik Rebane ◽  
P. Jakobsen ◽  
Ch. Larsen ◽  
P. H. Nielsen ◽  
Per-Erik Werner ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Mass Spectrometric ◽  
Organic Selenium

Mass-spectrometric studies. I. Benzo[b]thiophen, some alkyl and aryl derivatives, and the 1,1-dioxide and 2,3-dihydro-1,1-dioxide

1967 ◽  
Vol 20 (1) ◽  
pp. 103 ◽  
Author(s):  
QN Porter
Keyword(s):  
High Resolution ◽  
Mass Spectra ◽  
Mass Spectrometric ◽  
High Resolution Mass ◽  
Resolution Mass

The high-resolution mass spectra of benzo[b]thiophen, some alkyl and aryl derivatives, and the sulphone and 2,3-dihydrosulphone have been obtained; compositions of all significant ions in the spectra have been determined. Fragmentations of the unoxidized compounds are dominated by losses of C2H2 and CS units, while the sulphones undergo initial isomerization to cyclic sulphinates followed by expulsion of SO and fragments containing a C-O bond. Structures have been suggested for most of the ions observed.

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