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Mass spectra of indazolones and pyrazolones—II : 5‐pyrazolones
Author(s) -
Desmarchelier J. M.,
Johns R. B.
Publication year - 1969
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210020704
Subject(s) - pyrazolones , pyrazolone , chemistry , mass spectrum , medicinal chemistry , ion , organic chemistry
The mass spectral fragmentations of 3‐methyl‐5‐pyrazolone (I), 3‐methyl‐5‐pyrazolone‐1‐d 1 (II), 3‐methyl‐5‐pyrazolone‐1,4,4‐d 3 (III), 1‐acetyl‐3‐methyl‐5‐pyrazolone (IV), 3‐methyl‐5‐ethoxy‐pyrazole (V), 3,4‐dimethyl‐5‐pyrazolone (VI), 1,3‐dimethyl‐5‐pyrazolone (VII), 1‐acetyl‐5‐acetoxy‐3,4‐dimethylpyrazole (VIII), 1,2,3‐trimethyl‐5‐pyrazolone (IX), 3,4,4‐trimethyl‐5‐pyrazolone (X), 3,4,4‐trimethyl‐5‐pyrazolone‐1‐d 1 (XI), 3‐phenyl‐5‐pyrazolone (XII), 2‐acetyl‐3‐phenyl‐5‐pyrazolone (XIII) and 5‐acetoxy‐3‐phenylpyrazole (XIV) are reported. Comparison is made between the mass spectra of 5‐pyrazolones and 3‐indazolones. As for the latter compounds initial loss of ·N 2 R is preferred to loss of ·CHO, and is followed by loss of CO. The [M 1]ions are intense in the C‐methyl substituted pyrazolones, and unlike the 3‐indazolones, the pyrazolones do not show any significant loss of HCN from these ions. The mass spectra distinguish between certain isomeric 5‐pyrazolones.