Mass spectra of nitrogen heterocycles. II. Pyridyl Schiff bases

1973 ◽  
Vol 26 (5) ◽  
pp. 1031
Author(s):  
EJ Halbert ◽  
RJ Goldsack ◽  
JG Wilson
Keyword(s):  
Schiff Bases ◽  
Mass Spectra ◽  
Pyridyl Ring ◽  
Fragmentation Pattern ◽  
Methyl Radical ◽  
Azomethine Group ◽  
Major Reaction ◽  
Electron Impact Mass ◽  
Methoxy Substituent ◽  
Impact Mass

A number of anils of pyridine aldehydes and benzylideneaminopyridines were used to study positional effects of aromatic substituents and heteroatom placement on electron impact mass spectra. The simple fragmentation pattern of aromatic Schiff bases was obtained with all 3- and 4-pyridyl compounds when the other aromatic ring was unsubstituted phenyl, or in the case of anils, had a chloro or 3-methoxy substituent. Marked changes were brought about by a pyridyl ring at either end of the azomethine group when the heterocyclic nitrogen was adjacent to it. Displacement and rearrangement reactions then became dominant. Methoxy substitution para to the azomethine in all anils studied gave loss of methyl radical as the major reaction.

Synthesis and mass spectra of piperidine and piperazine N-oxyl radicals

1987 ◽  
Vol 52 (9) ◽  
pp. 2266-2273 ◽  
Author(s):  
Viera Kaliská ◽  
Štefan Toma ◽  
Ján Leško
Keyword(s):  
Liquid Crystals ◽  
Electron Impact ◽  
Mass Spectra ◽  
Fragmentation Pattern ◽  
Spin Probes ◽  
Electron Impact Mass ◽  
Impact Mass

It has been found that ultrasound could accelerate the synthesis of piperidine and piperazine N-oxyl radicals. These radicals were investigated for their utilization as spin probes for checking the properties of liquid crystals. Electron impact mass spectra of the N-oxyl radicals were recorded and their fundamental fragmentation pattern was proposed.

Electron impact mass spectra of new acyclic and macrocyclic sulphur-containing Schiff bases

1985 ◽  
Vol 20 (12) ◽  
pp. 789-791 ◽  
Author(s):  
Pietro A. Vigato ◽  
Sergio Sitran ◽  
Dolores Fregona ◽  
Sergio Daolio ◽  
Pietro Traldi
Keyword(s):  
Electron Impact ◽  
Schiff Bases ◽  
Mass Spectra ◽  
Electron Impact Mass ◽  
Impact Mass

Fragmentation of isomeric dideoxy derivatives of 1,6-anhydro-β-D-hexopyranoses under electron impact

1981 ◽  
Vol 46 (10) ◽  
pp. 2390-2403 ◽  
Author(s):  
František Tureček ◽  
Tomáš Trnka ◽  
Miloslav Černý
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Hydroxyl Group ◽  
Fragmentation Pattern ◽  
Positional Isomers ◽  
Deuterium Labeling ◽  
Stereochemical Assignment ◽  
Electron Impact Mass ◽  
Derivatives Of ◽  
Impact Mass

Electron impact mass spectra of all possible dideoxy derivatives of 1,6-anhydro-β-D-hexopyranoses and their sixteen specifically deuterium-labeled derivatives are reported. The spectra of positional isomers differ considerably making possible the reliable location of the hydroxyl group by mass spectrometry. The configuration of the hydroxyl group at C(2) and C(4) has only a negligible effect on the fragmentation pattern of stereoisomers. However, mass spectra of the C(3)-configurational isomers differ sufficiently to permit a stereochemical assignment. The fragmentation paths were elucidated by means of deuterium labeling and metastable spectra.

Notizen: Fast Pulsed Laser Induced Electron Generation for Electron Impact Mass Spectrometry

1988 ◽  
Vol 43 (12) ◽  
pp. 1151-1153 ◽  
Author(s):  
E. R. Rohwer ◽  
R.C. Beavis ◽  
C. Köster ◽  
J. Lindner ◽  
J. Grotemeyer ◽  
...  
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Ion Source ◽  
Electron Impact Mass Spectrometry ◽  
Uv Laser ◽  
Electron Generation ◽  
Medium Resolution ◽  
Electron Impact Mass ◽  
Impact Mass ◽  
Tof Ms

A new ultra fast electron impact (El) ion source is pre­sented that produces a very short, high intensity electron beam, allowing medium resolution mass spectra to be re­corded without pulsing the ion accelerating voltages in a time-of-flight mass spectrometer (TOF-MS). The ion source requires minimum modification of any TOF-MS equipped with an electrostatic ion reflector and UV-laser. El-spectra are presented for comparison with literature spectra.

scholarly journals Combination of LC-MS2 and GC-MS as a Tool to Differentiate Oxidative Metabolites of Zearalenone with Different Chemical Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Andreas A. Hildebrand ◽  
Erika Pfeiffer ◽  
Georg Damm ◽  
Manfred Metzler
Keyword(s):  
Mass Spectra ◽  
Ion Trap ◽  
Hydrolysis Product ◽  
Chemical Structures ◽  
Ion Trap Mass Spectrometer ◽  
Fragment Ions ◽  
Oxidative Metabolites ◽  
Electron Impact Mass ◽  
Negative Electrospray Ionization ◽  
Impact Mass

Recent studies on the mammalian and fungal metabolism of the mycotoxin zearalenone (ZEN) have disclosed the formation of six regioisomers of monohydroxy-ZEN and its reductive metabolite zearalenol (ZEL). Hydroxylation occurs at the aromatic ring or at one of four positions of the aliphatic macrocycle. In addition, an aliphatic ZEN epoxide, its hydrolysis product, and other products were identified in fungal cultures. In this paper, we report the product ion spectra of the [M-H]− ions of 22 oxidative metabolites of ZEN and ZEL, obtained by LC-MS2 analysis using a linear ion trap mass spectrometer with negative electrospray ionization. The MS2 spectra exhibit qualitative and quantitative differences which allow a clear distinction of most metabolites. Moreover, GC-MS analysis of the trimethylsilylated metabolites yields electron impact mass spectra with numerous fragment ions which can be used as fingerprint to confirm the chemical structure derived by LC-MS2 analysis.

ChemInform Abstract: MASS SPECTRA OF NITRONES. ELECTRON IMPACT MASS SPECTRA OF FLUORENONE NITRONES

1981 ◽  
Vol 12 (29) ◽  
Author(s):  
M. A. ABOU-GHARBIA ◽  
D. T. TERWILLIGER ◽  
M. M. JOULLIE ◽  
R. M. SRIVASTAVA
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Electron Impact Mass ◽  
Impact Mass
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