Spectres de masse d'hydrazino-2 benzo- et naphtothiazoles et d'hydrazones des méthyl-3 benzo- et naphtothiazolinones-2

1975 ◽  
Vol 53 (23) ◽  
pp. 3677-3680 ◽  
Author(s):  
Jean-Claude Richer ◽  
Philippe Lapointe ◽  
Martine Beljean ◽  
Michel Pays

Electron impact mass spectra are reported for the hydrazones of 3-methyl-2-benzothiazolinone (1), of 4-, 5-, 6-, and 7-chloro-3-methylbenzo-2-thiazolinones (2, 3, 4, and 5) and of 3-methyl-naphtho[2,1-d]-2-thiazolinone (6), as well as for 2-hydrazinobenzothiazole (7), for 4-, 5-, 6-, and 7-chloro-2-hydrazinobenzothiazoles (8, 9, 10, and 11) and for 2-hydrazinonaphtho[2,1-d]thiazole (12). The results obtained in the two series are compared. The 2-hydrazone and 3-methyl-benzo-2-thiazolinone and its derivatives all form a base peak corresponding to the molecular ion; fragmentation proceeds mainly by successive losses of·NH2, HCN, HCN, and then CS. Initial losses of N2H2, NH·, and NH3 are minor fragmentation routes.In the case of 2-hydrazinobenzothiazole and its derivatives, the base peak is still that of the molecular ion; however, the relative proportions of the various fragment ions vary with the position of sampling probe inside the apparatus. Thus it is concluded that the observed mass spectrum is that of a mixture of the possible hydrazone-hydrazine tautomers. The principal fragmentations involve the initial loss of NH3 (leading to a stabilized ion), of NH2· (probably from the hydrazone form), and of N2H2.(Journal Translation)


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Andreas A. Hildebrand ◽  
Erika Pfeiffer ◽  
Georg Damm ◽  
Manfred Metzler

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.



1990 ◽  
Vol 43 (1) ◽  
pp. 203 ◽  
Author(s):  
RG Gillis ◽  
QN Porter

In the electron impact mass spectrum of 2-(2°-R-phenyl)benzoic acids where R=H, NO2, OCH3, COOH, or Br, an abundant fragment ion m/z 197 is formed by an ipso substitution in which R is expelled as a radical. The structure of the ion m/z 197 has been shown by collision-activated dissociation to be identical with that of the protonated molecule formed by methane chemical ionization of 6H-dibenzo[ b,d ]pyran-6-one.



1991 ◽  
Vol 44 (6) ◽  
pp. 863 ◽  
Author(s):  
LK Dyall ◽  
JA Ferguson

3-Alkyl-2,1-benzisoxazoles underwent complex fragmentations under electron impact, and the balance between available pathways changed considerably across the range of alkyl groups (methyl, ethyl, isopropyl and t-butyl). The primary loss of CO is accounted for in terms of rearrangement of the initial molecular ion to an alkylimine ketene species. The 3-methyl compounds lost methyl as methyl cyanide, acylium cation or ketene, but the higher alkyl groups were chiefly lost as alkyl cations or by internal fragmentations in which some novel ortho-effects were noted. Most of these pathways were confirmed by B/E linked scans, and useful comparisons were made with the e.i . spectra of N- alkylanthranilic acids. All of these isoxazoles underwent partial decomposition on the heated probe.



1976 ◽  
Vol 29 (2) ◽  
pp. 301
Author(s):  
MJ Lacey ◽  
JS Shannon

Positional integrity of the label is maintained in the molecular ions of 2-ben~oyl[18O]benzoic acid prior to a number of primary fragmentation modes. Positional integrity is also evident for some source and metastable reactions of the protonated molecular ions formed in its chemical ionization (H2) mass spectrum. The (M-Ph)+ ions formed in the electron impact mass spectrum, however, fragment further after complete equilibration of their oxygen atoms.



1976 ◽  
Vol 29 (2) ◽  
pp. 257 ◽  
Author(s):  
CG Macdonald ◽  
RL Martin ◽  
AF Masters

The progressive replacement by sulphur in the isostructural planar nickel compounds bis(2,2,6,6- tetramethylheptane-3,5-dionato)nickel(11) (1), bis(2,2,6,6-tetramethyl-5-thioxoheptan-3-onato)nickel(11) (2) and bis(2,2,6,6-tetramethylheptane-3,5-dithionato)nickel(11) (3) causes a change in their positive electron impact mass spectra from one dominated by metal-containing fragment ions (1) to one But 1 dominated by oxidized ligands (3). Comparisons are also made with the spectra of tris(monothio-dipivaloylmethanato)cobalt(111) and bis(1,l,1-trifluoro-4-thioxopentan-2-onato)nickel (11). Mass spectral peaks corresponding to mixed ligand species were observed when mixtures of (1) and (2) were vaporized in the mass spectrometer.





1988 ◽  
Vol 43 (12) ◽  
pp. 1151-1153 ◽  
Author(s):  
E. R. Rohwer ◽  
R.C. Beavis ◽  
C. Köster ◽  
J. Lindner ◽  
J. Grotemeyer ◽  
...  

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.



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