A Neighboring Group Effect of Carbonyl as Shown in the Mass Fragmentation Patterns of 4-Oxochroman-5-acetic Acids and of Some Related Compounds

1988 ◽  
Vol 41 (4) ◽  
pp. 535 ◽  
Author(s):  
H Duewell ◽  
TJ Haig
Keyword(s):  
Mass Spectra ◽  
Methyl Esters ◽  
Radical Cations ◽  
Group Effect ◽  
Neighboring Group ◽  
Electron Impact Mass ◽  
Fragmentation Patterns ◽  
Related Compounds ◽  
Impact Mass ◽  
Acetic Acids

Two examples of a neighbouring group effect of carbonyl first observed with 4-oxochroman-5-acetic acids are shown to occur quite generally during electron impact mass spectrometry of 2-acylbenzeneacetic acids, 2-acylbenzoic acids and their methyl esters. The free acids readily give the [parent - CO2] ion. 2-Acylbenzeneacetic acids and their methyl esters after loss of water or methanol, respectively, as a first step, lead to very stable isobenzofuran radical cations which form the base peaks in the mass spectra of the esters.

scholarly journals Substituent Effects on EI-MS Fragmentation Patterns of 5-Allyloxy-1-aryl-tetrazoles and 4-Allyl-1-aryl-tetrazole-5-ones; Correlation with UV-Induced Fragmentation Channels

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3282
Author(s):  
Alina Secrieru ◽  
Rabah Oumeddour ◽  
Maria L. S. Cristiano
Keyword(s):  
Theoretical Calculations ◽  
Substituent Effects ◽  
Radical Cations ◽  
Electronic Effects ◽  
Diverse Range ◽  
The Matrix ◽  
Electron Impact Mass ◽  
Fragmentation Patterns ◽  
Tetrazole Derivatives ◽  
Impact Mass

1,4- and 1,5-disubstituted tetrazoles possess enriched structures and versatile chemistry, representing a challenge for chemists. In the present work, we unravel the fragmentation patterns of a chemically diverse range of 5-allyloxy-1-aryl-tetrazoles and 4-allyl-1-aryl-tetrazolole-5-ones when subjected to electron impact mass spectrometry (EI-MS) and investigate the correlation with the UV-induced fragmentation channels of the matrix-isolated tetrazole derivatives. Our results indicate that the fragmentation pathways of the selected tetrazoles in EI-MS are highly influenced by the electronic effects induced by substitution. Multiple pathways can be envisaged to explain the mechanisms of fragmentation, frequently awarding common final species, namely arylisocyanate, arylazide, arylnitrene, isocyanic acid and hydrogen azide radical cations, as well as allyl/aryl cations. The identified fragments are consistent with those found in previous investigations concerning the photochemical stability of the same class of molecules. This parallelism showcases a similarity in the behaviour of tetrazoles under EI-MS and UV-irradiation in the inert environment of cryogenic matrices of noble gases, providing efficient tools for reactivity predictions, whether for analytical ends or more in-depth studies. Theoretical calculations provide complementary information to articulate predictions of resulting products.

Mass Spectra of Sodium N-Alkyl and N,N-Dialkyl Dithiocarbamates and Some Related Compounds

1976 ◽  
Vol 59 (3) ◽  
pp. 622-632 ◽  
Author(s):  
Francis I Onuska ◽  
Michael E Comba
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Fragmentation Behavior ◽  
Zinc Salts ◽  
Electron Impact Mass ◽  
Related Compounds ◽  
Impact Mass

Abstract Electron impact mass spectra of 8 sodium alkyl and dialkyl dithiocarbamate salts are reported with the spectra of 2 dithiocarbamate zinc salts and N′,N′-dimetliyl-N,N-dimethylthiocarbamylsulfenamide. The investigated compounds all gave molecular ions, and generalized descriptions of their fragmentation behavior are presented.

Electron impact mass spectra of hexamethylphosphorictriamide (HMPT) and related compounds

1985 ◽  
Vol 20 (4) ◽  
pp. 318-321 ◽  
Author(s):  
Raymond Bouriet ◽  
Daniel Stahl ◽  
Jean-Claude Bollinger ◽  
ThéOphile Yvernault
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Electron Impact Mass ◽  
Related Compounds ◽  
Impact Mass

Electron Impact Mass Spectra of 3-Aryl-3-hydroxyl-2,2,4,4-tetramethylcyclobutanones and Related Compounds

2000 ◽  
Vol 47 (4B) ◽  
pp. 907-912 ◽  
Author(s):  
Shaw-Tao Lin ◽  
Wen-Chung Lin ◽  
Richard Yung-Ho Chao ◽  
Ching-Liang Huang
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Electron Impact Mass ◽  
Related Compounds ◽  
Impact Mass
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