Differentiation of Ionised Benzimidazole from its Isomeric α-Distonic Ion by Collision-Induced Dissociation and Neutralisation—Reionisation Mass Spectrometry
Restricted accessResearch articleFirst published online August, 2005
Differentiation of Ionised Benzimidazole from its Isomeric α-Distonic Ion by Collision-Induced Dissociation and Neutralisation—Reionisation Mass Spectrometry
Ionised benzimidazole and its isomeric α-distonic ion (or ionised ylid) have been
examined by recording their metastable ion, collision-induced dissociation and
neutralisation–reionisation mass spectra. These tautomers may be distinguished by careful
consideration of key features of the collision-induced dissociation spectra, with or
without prior neutralisation and reionisation. Formation of doubly-charged ions by charge
stripping occurs preferentially when the α-distonic ion is subjected to collision. This
α-distonic ion survives neutralisation and reionisation, thus establishing that the
corresponding ylid is stable on the microsecond time frame. The effects of benzannulation
on the ease of differentiation of classical and distonic radical cations derived from
biologically important heterocycles are considered.
GilchristT.L.,
Heterocyclic Chemistry, 3rd Edition.
Longman, New York, USA
(1991).
2.
MatsumotoT.OhishiM.InoueS.,
“Selective cross-acyloin condensation catalyzed by thiazolium salt.
Formation of 1-hydroxy 2-one from formaldehyde and other aldehydes”,
J. Org. Chem.50, 603 (1985).
3.
StetterH.DämbkesG.,
“Über die präparative Nutzung der Thiazoliumsalz-katalysierten Acyloin-
und Benzoin-Bildung; II1. Herstellung unsymmetrischer Acyloine und
α-Diketone”, Synthesis6, 403 (1977).
4.
LavoratoD.J.TerlouwJ.K.DargelT.K.KochW.McGibbonG.A.SchwarzH.,
“Observation of the Hammick intermediate: Reduction of the
Pyridine-2-ylid in the gas phase”, J. Am. Chem. Soc.118, 11898 (1996).
5.
LavoratoD.J.TerlouwJ.K.McGibbonG.A.DargelT.K.KochW.SchwarzH.,
“Generation of neutral and cationic hydrogen shift isomers of pyridine: A
combined experimental and computational investigation”, Int. J.
Mass Spectrom. Ion Processes179/180, 7 (1998).
6.
TrikoupisM.A.LavoratoD.J.TerlouwJ.K.RuttinkP.J.A.BurgersP.C.,
“Lowering large 1,2-H shift barriers by protontransport catalysis: The
challenging case of the pyridine radical cation”, Eur. J. Mass
Spectrom.5, 431 (1999).
7.
DargelT.K.KochW.LavoratoD.J.McGibbonG.A.TerlouwJ.K.SchwarzH.,
“Pyrazine diradicals, carbenes, ylides, and distonic ions probed by
theory and experiment”, Int. J. Mass Spectrom.185–187, 925 (1999).
8.
LavoratoD.J.DargelT.K.KochW.McGibbonG.A.SchwarzH.TerlouwJ.K.,
“Pyrimidine-ylidenes produced using neutralization–reionization mass
spectrometry and probed by density functional methods”, Int. J.
Mass Spectrom.210/211, 43 (2001).
9.
KarapanayiotisT.Dimopoulos-ItalianoG.BowenR.D.TerlouwJ.K.,
“Reactions of ionised pyridazine, aminopyrazine and aminopyridine and
their isomeric α-distonic ions”, Int. J. Mass Spectrom.236, 1 (2004).
10.
McGibbonG.A.HeinemannC.LavoratoD.J.SchwarzH.,
“Imidazol-2-ylidene: Generation of a Missing Carbene and Its Dication by
Neutralization-Reionizatin and Charge-Stripping Mass Spectrometry”,
Angew. Chem. Int. Edn. Engl.36, 1478 (1997).
McGibbonG.A.HrušákJ.LavoratoD.J.SchwarzH.TerlouwJ.K.,
“The Thiazole Ylide: A Frequently Invoked Intermediate Is a Stable
Species in the Gas Phase”, Eur. J. Chem.3, 232 (1997).
13.
BohmeD.K.,
“Proton transport in the catalyzed gas-phase Isomerization of Protonated
Molecules”, Int. J. Mass Spectrom. Ion Processes115, 95 (1992).
14.
ChalkA.RadomL.,
“Proton transport catalysis. A systematic study of the rearrangement of
the isoformyl cation to the formyl cation”, J. Am. Chem.
Soc.119, 7573 (1997).
15.
PhilipsM.A.,
“The formation of 2-substituted benz imidazoles”,
J. Chem. Soc.2393 (1928).
16.
VogelA.,
Textbook of Practical Organic Chemistry, 4th Edn,
revised by FurnissB.S.HannafordA.J.RogersV.SmithP.W.G.TatchellA.R.,
Longman, London, UK, p.
888 (1978) .
17.
CoperlandR.A.B.DayA.R.,
“The preparation and reactions of 2-benzimidazolecarboxylic acid and
2-benzimidazole-acetic acid”, J. Am. Chem. Soc.65, 1072 (1943).
18.
GrundmannC.KreutzbergerA.,
“Triazines XIII. The ring cleavage of s-triazine by primary amines. A new
method for the synthesis of heterocycles”, J. Am. Chem.
Soc.77, 6559 (1955).
19.
VogelA.,
Textbook of Practical Organic Chemistry, 4th Edn,
revised by FurnissB.S.HannafordA.J.RogersV.SmithP.W.G.TatchellA.R.,
Longman, London, UK, pp.
289–292 (1978) .
20.
van GarderenH.F.RuttinkP.J.A.BurgersP.C.McGibbonG.A.TerlouwJ.K.,
“Aspects of the CH5N2 potential-energy surface-ions
CH3NHNH+, CH3NNH2+ and
CH2NHNH2+ and radicals
CH2NHNH2• studied by theory and
experiment”, Int. J. Mass Spectrom. Ion Processes121, 159 (1992).
21.
MontgomeryJ.A.FrischM.J.OchterskiJ.W.PeterssonG.A.,
“A complete basis set model chemistry. VI. Use of density functional
geometries and frequencies”, J. Chem Phys.110, 2822 (1999).
22.
MontgomeryJ.A.FrischM.J.OchterskiJ.W.PetersonG.A.,
“A complete basis set model chemistry. VII. Use of the minimum population
localization method”, J. Chem Phys.112, 6532 (2000).
BurgersP.C.HolmesJ.L.MommersA.A.TerlouwJ.K.,
“Neutral products of ion fragmentations: HCN and HNC identified by
collisionally induced dissociative ionization”, Chem. Phys.
Lett.102, 1 (1983).
25.
BurgersP.C.HolmesJ.L.MommersA.A.SzulejkoJ.E.TerlouwJ.K.,
“Collisionally induced dissociative ionization of neutral products from
unimolecular ion fragmentations. 1 - Neutral product structures”,
Org. Mass Spectrom.19, 442 (1984).
26.
HolmesJ.L.MommersA.A.,
“An ion beam deflector for use in the analysis of neutral products of ion
fragmentations”, Org. Mass Spectrom.19, 460 (1984).
27.
HopC.E.C.A.DakabuM.HolmesJ.L.,
“Do the aminopyridine molecular ions display aniline- or pyridine-type
behaviour?”, Org. Mass Spectrom.23, 609 (1988).
28.
MaquestiauA.van HaverberkeY.FlammangR.PardoM.C.ElgueroJ.,
“Fragmentation d'azoles sous l'impact electronique
VI-indazole”, Org. Mass Spectrom.10, 558 (1975).
29.
HolmesJ.L.LossingF.P.TerlouwJ.K.BurgersP.C.,
“Novel gas-phase ions. The radical cations
[CH2XH]+· (X = F, Cl, Br, I, OH, NH2, SH) and
[CH2CH2NH3]+·”,
Can. J. Chem.61, 2305 (1983).
30.
YatesB.F.BoumaW.J.RadomL.,
“Ylide dications: An examination of first- and second-row
systems”, J. Am. Chem. Soc.108, 6545 (1986).
31.
HammerumS.,
“Distonic radical cations in gaseous and condensed
phase”, Mass Spectrom. Rev.7, 123 (1988).
32.
ShayB.J.EberlinM.N.CooksR.G.WesdemiotisC.,
“Ion-molecule reactions and collision-activated dissociation of
C4H+·4 isomers: A case study in the use of the
MS3 capabilities of a pentaquadrupole mass spectrometer”,
J. Am. Soc. Mass Spectrom.3, 518 (1992).
33.
GerbauxP.Barbieux-FlammangM.Van HaverbekeY.FlammangR.,
“Characterization of ionized heterocyclic carbenes by ion-molecule
reactions”, Rapid Commun. Mass Spectrom.13, 1707 (1999).
34.
GerbauxP.Barbieux-FlammangM.TerlouwJ.K.FlammangR.,
“Definitive characterization of some C5H5N + and
C6H7N+ radical cations by associative ion-molecule
reactions”, Int. J. Mass Spectrom.206, 91 (2001).
