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Mass spectra of halogenated esters 6—Methyl esters of some trihalogenated propanoic and butanoic acids
Author(s) -
Korhonen Ilpo O. O.
Publication year - 1984
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.1210190209
Subject(s) - chemistry , halogen , fragmentation (computing) , mass spectrum , propanoic acid , medicinal chemistry , base (topology) , cleavage (geology) , stereochemistry , mass spectrometry , organic chemistry , mathematical analysis , alkyl , mathematics , geotechnical engineering , chromatography , fracture (geology) , computer science , engineering , operating system
The mass spectral fragmentation of trihalogenated methyl esters, formed in the reactions of monochlorinated methyl propenoates and 2‐butenoates with Cl 2 , BrCl and Br 2 , have been investigated. In most cases α‐cleavage gives the base peak, [COOCH 3 ] + , the peaks originating from the subsequent losses of one or two halogen atoms also being abundant. The primary loss of a halogen atom is more prominent in the C 4 derivatives, Br˙ and Cl˙ being preferentially lost from the 2‐ and 3‐positions, respectively. The McLafferty rearrangement yields in one case the base peak; the 2‐halo compounds could in general be distinguished by that fragmentation. Typical for all 2‐bromo‐substituted methyl butanoates studied is the base peak, [C 3 H 3 ] + , at m / z 39, and for some 3‐halo compounds the peaks at m / z 95, [C 2 H 4 ClO 2 ] + and 139, [C 2 H 4 BrO 2 ] + .