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

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.

1988 ◽  
Vol 41 (4) ◽  
pp. 535 ◽  
Author(s):  
H Duewell ◽  
TJ Haig

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.


2005 ◽  
Vol 19 (18) ◽  
pp. 2563-2568 ◽  
Author(s):  
Guadalupe Pérez-Caballero ◽  
Federico Jiménez-Cruz ◽  
Pablo Hernández Matamoros ◽  
José Guadalupe García ◽  
Fernando Cortés-Guzmán ◽  
...  

2008 ◽  
Vol 27 (1) ◽  
pp. 65 ◽  
Author(s):  
Hassan K. Ibrahim ◽  
Sayed H. El-Tamany ◽  
Reda F. El-Shaarawy ◽  
Ibrahim M. El-Deen

2-Substituted benzimidazoles (3) and (4a-c) were prepared via condensation of ethyl 2-thionyl-pyruvate (1) and hydrazidoyl derivatives (2a-c) with o-phenylene diamine in acetic acid. Acetylation of compound (4a) with acetic anhydride yielded the corresponding N-acetyl derivative (5). Treatment of compound 4b with hydrazine hydrate gave the corresponding hydrazino derivative (6). Reaction of 2-[(2-thionyl)acetyl)] benzimidazole (3) with hydrazine hydrate gave the pyrazolyl derivative (7) and hydrazino derivative (8). Alkylation of compound 3 with alkyl halide gave the corresponding 2,3-disubstituled benzimidazoles (9a, b). Pyrrolo[1,2-a] benzimidazole derivatives 10 and 11 were prepared via cyclocondensation of compound 3 with acetic anhydride in presence of AcONa and phosphorus oxychloride. The electron impact mass spectra of both of the above series of compounds have also been recorded and their fragmentation patterns are discussed.


2000 ◽  
Vol 14 (3) ◽  
pp. 115-120 ◽  
Author(s):  
Lúcia Fernanda C. C. Leite ◽  
Eliezer J. Barreiro ◽  
Mozart N. Ramos ◽  
João Bosco P. Silva ◽  
Suely L. Galdino ◽  
...  

This report describes the results of a study of the electron impact mass spectrometry behaviour of 20 new compounds of a series of 3-[3-(4-aryl)-1,2,4-oxadiazole-5-yl] acyl arylaldehyde hydrazone derivatives. The most relevant possible fragmentation patterns of this class of compounds under electron impact are outlined.


1993 ◽  
Vol 280 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Varoujan Yaylayan ◽  
Alexis Huyghues-Despointes ◽  
Martine C. Bissonnette ◽  
J.R.Jocelyn Paré

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