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Mass spectrometry of 3,4‐dihydroquinazolin‐4‐ones of pharmaceutical interest. Part 3 . Electron ionization mass spectra of 2‐substituted‐3‐(5′‐pyrazolyl)‐4(3 H )‐quinazolinones
Author(s) -
Ferrugia Mirella,
Bajardi Maria Luisa,
Ceraulo Leopoldo,
Plescia Salvatore
Publication year - 1992
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570290247
Subject(s) - chemistry , fragmentation (computing) , substituent , electron ionization , mass spectrum , mass spectrometry , ion , metastability , mass , ionization , aryl , analytical chemistry (journal) , chemical ionization , medicinal chemistry , organic chemistry , chromatography , alkyl , computer science , operating system
The fragmentation reactions induced by electron impact of eighteen title compounds has been investigated with the aid of low beam energy spectra (14 eV, nom. value), metastable ion detection, high resolution measurements and labelling experiments. The loss of the 4‐carbonyl oxygen together with the 3‐substituent, which constitutes a characteristic fragmentation route of 3‐aryl and 3‐heteroaromatic substituted‐4(3 H )‐quinazolinones, is again observed, but the presence of a carboxyethyl group at the 4′‐position of the pyrazole ring is responsible of an anomalous loss of 47 daltons from the molecular ion. Lastly, a comparison with the previously described behaviour of 3‐(5′‐isoxazolyl) derivatives was carried out.