Hydrogen-shift isomerism: mass spectrometry of isomeric benzenesulfonate and 2-, 3- and 4-dehydrobenzenesulfonic acid anions in the gas phase

2005 ◽  
Vol 40 (8) ◽  
pp. 1064-1071 ◽  
Author(s):  
Julius Ben-Ari ◽  
Alex Etinger ◽  
Adrian Weisz ◽  
Asher Mandelbaum
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Hydrogen Shift

Observation of 13C rearrangement in [13C2]biphenylene formed from benzyne on pyrolysis of [1,6-13C2]phthalic anhydride and [2a,3-13C2]benzocyclobutenedione

1984 ◽  
Vol 37 (8) ◽  
pp. 1643 ◽  
Author(s):  
M Barry ◽  
RFC Brown ◽  
FW Eastwood ◽  
DA Gunawardana ◽  
C Vogel
Keyword(s):  
Mass Spectrometry ◽  
Sulfur Dioxide ◽  
Isotopic Composition ◽  
Gas Phase ◽  
Phthalic Anhydride ◽  
Carbon Skeleton ◽  
Hydrogen Shift ◽  
Thermal Elimination ◽  
A Minor

Examination of [13C2]biphenylene formed by gas phase pyrolysis of doubly labelled benzyne precursors shows that the principal pyrolytic process leads to overall 1,2→1,3 rearrangement of the C6H4 carbon skeleton either in an intermediate C7H4O before decarbonylation or in benzyne itself. A minor process involves an apparent 1,3-hydrogen shift. [1,2-13C2]Ethyne-1,2-diylbistrimethylsilane was acylated with 3-(2,5-dihydro-1,1-dioxothien- 2-yl)propanoyl chloride and the resulting ketone was desilylated to yield 5-(2,5-dihydro-1,l-dioxo-thien-2-yl)[1,2-13C2]pent-1-yn-3-one. Thermal elimination of sulfur dioxide and cyclization followed by dehydrogenation yielded [7,7a-13C2]-2,3-dihydro-1H-inden-1-one which was oxidized and dehydrated to give [3a,4-13C2]isobenzofuran-1,3-dione. This doubly labelled phthalic anhydride was diluted to approximately 5% 13C2 and the resulting material was converted via benzenediazonium- 2-carboxylate into biphenylene at 84�, and pyrolysed at 830� to yield biphenylene, and a sample diluted to 7.5% was converted into [2a,3-13C2]benzocyclobutenedione which was pyrolysed at 650�, 750� and 830� to yield further samples of biphenylene. The biphenylene samples were examined by mass spectrometry at 20 eV to determine their isotopic composition and by 13C n.m.r. spectroscopy to determine the distribution of labelling.

Transposition des cations radicaux aminés en spectrométrie de masse

1984 ◽  
Vol 62 (5) ◽  
pp. 931-938 ◽  
Author(s):  
Henri Edouard Audier ◽  
Jean Pierre Denhez ◽  
Arielle Milliet ◽  
Georges Sozzi
Keyword(s):  
Mass Spectrometry ◽  
Nitrogen Atom ◽  
Gas Phase ◽  
Internal Energy ◽  
Experimental Results ◽  
Ammonia Molecule ◽  
Hydrogen Shift ◽  
Spectrométrie De Masse ◽  
Good Agreement

It is demonstrated in mass spectrometry that alkylamines substituted at C2 and containing weak internal energy isomerize in the gas phase into intermediary ions composed of ionized cyclopropanes complexed with an ammonia molecule. This process is induced by a C3 hydrogen shift on the nitrogen atom. After opening of the cyclopropane, the dissociation of these complexes leads to m/z 44, 58, and 72 ions having [CH3(CH2)nCH NH2] structures. The mechanism of their formation is demonstrated by the MIKE spectra of 13C and deuterium labelled compounds. The experimental results are in good agreement with those described by Gross etal., who studied the fragmentation of the complexes formed during the reaction between substituted ionized cyclopropanes and ammonia in the gas phase.

Mass Spectrometry and Gas-Phase Chemistry of Anilines

ChemInform ◽  
2007 ◽  
Vol 38 (30) ◽  
Author(s):  
Marcos N. Eberlin ◽  
Daniella Vasconcellos Augusti ◽  
Rodinei Augusti
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

The mass spectrometry-induced cyclization of protonated N-[2-(benzoyloxy)phenyl]-benzamide: A gas-phase analog of a solution reaction

2006 ◽  
Vol 249-250 ◽  
pp. 21-30 ◽  
Author(s):  
Joseph T. Moolayil ◽  
M. George ◽  
R. Srinivas ◽  
N.S. Swamy ◽  
Amber L. Russell ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Solution Reaction
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