Electron impact studies. XV. Skeletal rearrangement fragments in the mass spectra of aromatic N-oxides

The mass spectra of representative series of simple alkyl acetoacetates, alkyl acetothioacetates, and some unsaturated esters derived from unsaturated alcohols or phenols are reported and discussed. The fragmentation schemes have been established by high resolution measurements, appropriate metastable ions, and by deuterium and 18O labelling. Many of the spectra show significant skeletal rearrangement fragments arising from either loss of carbon monoxide or carbon dioxide.

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Electron impact studies. XI. Mass spectra of aromatic azoxy compounds. Skeletal rearrangement upon electron impact

Australian Journal of Chemistry ◽

10.1071/ch9671601 ◽

1967 ◽

Vol 20 (8) ◽

pp. 1601 ◽

Cited By ~ 23

Author(s):

JH Bowie ◽

RG Cooks ◽

GE Lewis

Keyword(s):

Electron Impact ◽

Mass Spectra ◽

Molecular Ions ◽

Skeletal Rearrangement ◽

Impact Studies ◽

Azoxy Compounds

The mass spectra of 15 aromatic azoxy compounds are reported and discussed. The spectra exhibit pronounced molecular ions, and fragmentation modes which are produced by both simple cleavage and complex skeletal reorganization processes.

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Electron impact studies. XXXVII. Skeletal-rearrangement fragments in the mass spectra of alkyl and aryl isoxazoles

Australian Journal of Chemistry ◽

10.1071/ch9690563 ◽

1969 ◽

Vol 22 (3) ◽

pp. 563 ◽

Cited By ~ 53

Author(s):

JH Bowie ◽

RKMR Kallury ◽

RG Cooks

Keyword(s):

Electron Impact ◽

Mass Spectra ◽

Skeletal Rearrangement ◽

Deuterium Labelling ◽

Isoxazole Ring ◽

Impact Studies ◽

Rearrangement Processes

The mass spectra of substituted isoxazoles are reported and discussed. The spectra of isoxazoles are strikingly different from those of oxazoles because the initial fragmentations of isoxazoles involve N-O bond fission. Specific skeletal-rearrangement processes are observed in many spectra, and it is proposed that they proceed through azirine and oxazole intermediates. Certain fragmentations have been studied by deuterium labelling. The hydrogens attached to an isoxazole ring do not randomize with the hydrogens of the methyl and phenyl substituents.

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Electron impact studies. XL. Negative-ion mass spectra of organosulphur compounds : Thioglycollic acids and arylsulphinylamines

Australian Journal of Chemistry ◽

10.1071/ch9690153 ◽

1969 ◽

Vol 22 (1) ◽

pp. 153 ◽

Cited By ~ 14

Author(s):

JH Bowie ◽

F Duus ◽

S Lawesson ◽

FCV Larsson ◽

J+ Madsen

Keyword(s):

Electron Impact ◽

Mass Spectra ◽

Molecular Ions ◽

Negative Ion ◽

Skeletal Rearrangement ◽

Marked Contrast ◽

Impact Studies ◽

Positive Ion ◽

Hydrogen Rearrangement

The negative-ion mass spectra of thioglycollic esters and S- alkylthioglycollic acids exhibit ions produced by simple cleavage and/or cleavage with hydrogen rearrangement. Similar spectra of arylsulphinylamines show pronounced molecular ions together with simple cleavage fragments. No skeletal-rearrangement fragments are present in the negative-ion spectra, in marked contrast with those observed in the corresponding positive-ion spectra.

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