Effects of the alkyl portion of the alkoxy group on the mass spectrometric fragmentation pathways for the 1-alkoxy-9-oxabicyclo[3.3.1]nonane system and comparison with the 1-alkoxy-9-methyl-9-azabicyclo[3.3.1]nonane system

1978 ◽  
Vol 43 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Herman O. Krabbenhoft ◽  
Woodfin V. Ligon
Keyword(s):  
Alkoxy Group ◽  
Mass Spectrometric ◽  
Fragmentation Pathways ◽  
Mass Spectrometric Fragmentation

Formation of Organometallic Species, [M – H]+ Ions and Radical Cations upon Mass Spectrometric Fragmentation of Mercury–Crown Ether Complexes

2009 ◽  
Vol 15 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Rafał Frański ◽  
Błażej Gierczyk
Keyword(s):  
Mass Spectrometry ◽  
Crown Ether ◽  
Radical Cations ◽  
Mass Spectrometric ◽  
Tandem Mass ◽  
Fragmentation Pathways ◽  
Factors Influencing ◽  
Crown Ether Complexes ◽  
Mass Spectrometric Fragmentation ◽  
Ether Molecule

Mass spectrometric fragmentation pathways of [M + HgClO4]+ (M – crown ether molecule), determined by tandem mass spectrometry experiments, are discussed in detail. The decomposition of [M + HgClO4]+ proceeds along three fragmentation pathways: formation of [M – H]+ ions, formation of organometallic species, namely [M – H + Hg]+ ions, and formation of radical cations [M]+•. The factors influencing these processes, namely crown ether cavities and the presence of electron withdrawing/electron donor groups, have been discussed.

Synthesis of ethyl ortho-substituted benzoylacetates and investigation of the influence of ortho-substituents on keto-enol tautomerism and MS fragmentation behaviour

1988 ◽  
Vol 53 (4) ◽  
pp. 839-850 ◽  
Author(s):  
Dieter Sicker ◽  
Gerhard Mann
Keyword(s):  
Nmr Spectroscopy ◽  
Parent Compound ◽  
Mass Spectrometric ◽  
Acid Chlorides ◽  
Fragmentation Pathways ◽  
Keto Esters ◽  
H Nmr ◽  
Mass Spectrometric Fragmentation

A series of seven ethyl 2-acetyl-(2-substituted benzoyl)acetates II-VIII was synthesized, together with their parent compound I, from the corresponding acid chlorides. The tautomerism of these β-tricarbonyl compounds in tetrachloromethane was studied by 1H NMR spectroscopy and former results concerning this problem were critically evaluated. A further series of seven ortho-substituted ethyl benzoylacetates X-XV and XVII was obtained from the corresponding precursors II-VIII. The keto-enol tautomerism of these β-keto esters was studied by 1H NMR in different solvents and compared with ethyl benzoylacetate IX as standard. Differences caused by the ortho-substituents are discussed. Investigation of the mass spectrometric fragmentation of the β-keto esters IX-XV and XVII showed both common fragmentation pathways due to the same substance class and typical differences in relative intensities according to the nature of the ortho-substituent.

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