Abstract
Mass spectrometry and tandem mass spectrometry techniques have been used to study the gas phase ion chemistry of isomeric α-cyanoethylindoles obtained by photochemical reactions. Both the fragmentation reactions occurring in the ion source, as well as metastable decompositions produced by the molecular and selected fragment ions, have allowed us to structurally characterize and differentiate each isomer from the others. The experiments, carried out also on deuterium labeled analogs, have shown the role exerted by the α-cyanoethyl substituent and by its position at the indolic ring on gas phase reactions that resulted to be distinctive and selective for each isomer. Ab initio theoretical calculations have been used to evaluate the stability and chemico-physical properties of different ion structures.
Article PDF
Similar content being viewed by others
References
Beljanski, M.; Beljanski, M. S. Three Alkaloids as Selective Destroyers of Cancer Cells in Mice. Synergy with Classic Anticancer Drugs. Oncology 1986, 43, 198–203.
Pindur, U.; Erfanian-Abdoust, H. [4 + 2]Cycloadditions of Pyrano[3,4-b]Indol-3-ones with 1,2-bis-Acceptor Substituted Ethenes: First Evidence for a Non-Concerted Dields-Alder Step. Heterocycles 1990, 31, 1751–1761.
Gribble G. W. In The Alkaloids, Vol. 39; Brossi, A., Ed.; Academic Press: New York, 1990; p 239.
Powers, J. C. The Mass Spectrometry of Simple Indoles. J. Org. Chem. 1968, 33, 2044–2050.
Marx, M.; Djerassi, C. Mass Spectrometry in Structural and Stereochemical Problems. CXLIX. The Question of Ring Expansion in the Fragmentation of 13C-Labeled Nitrogen Heterocycles. J. Am. Chem. Soc. 1968, 90, 678–681.
Corval, M. Elimination sous Impact Electronique de HCN and H· a partir de l’Indole. Comparison avec l’Indolizine. Org. Mass Spectrom. 1979, 14, 213–219.
Corval, M. An Electron Impact Study of HCN Elimination from Indole by Use of 13C Labeling. Org. Mass Spectrom. 1981, 16, 444–447.
Rodriguez, J. G.; Canoira, L. Electron Impact Mass Spectrometry of Indoline Derivatives. Int. J. Mass Spectrom. Ion Processes 1995, 142, 23–29.
Rodriguez, J. G.; Urrutia, A.; Canoira, L. Electron Impact Mass Spectrometry of Indole Derivatives. Int. J. Mass Spectrom. Ion Processes 1996, 152, 97–110.
Erra-Balsells, R. Mass Spectral Fragmentation Patterns of 2-Methyl-, 3-Methyl-, 2,3-Dimethyl-, 2-Aryl-, and 3-Phenylindole Derivatives. J. Heterocyclic Chem. 1987, 24, 1117–1120.
Erra-Balsells, R. Mass Spectral Fragmentation Patterns of 2,3-Diphenylindole Derivatives and Dibenzo[ac]Carbazoles. J. Heterocyclic Chem. 1988, 25, 221–224.
Porter, Q. N. In Mass Spectrometry of Heterocyclic Compounds 2nd ed.; J. Wiley and Sons: New York, 1985; pp 555–580 and references cited therein.
Giorgi, G.; Ponticelli, F.; Czira, G.; Vékey, K. Characterization and Differentiation of Heterocyclic Isomers. Tandem Mass Spectrometry and Molecular Orbital Calculations on 3-Methylisoxazolo- and 2-Methyloxazolo-Pyridines. J. Am. Soc. Mass Spectrom. 1995, 6, 962–971.
Giorgi, G.; Anzini, M.; Cappelli, A.; Corelli, F.; Vomero, S. Characterization and Differentiation of Heterocyclic Isomers. Part 2. Mass Spectrometry and Molecular Orbital Calculations on Pyrrolo [1,2-a][1,4] Benzodiazepin-4-one, -6-one, -4,6-dione. J. Am. Soc. Mass Spectrom. 1996, 7, 653–663.
Giorgi, G.; Salvini, L.; Ponticelli, F. Structural Characterization and Regiochemical Differentiation of Modified Isomeric Tryptophans. J. Am. Soc. Mass Spectrom. 2002, 13, 1298–1303.
Giorgi, G.; Salvini, L.; Ponticelli, F. Gas Phase Reactivity of Isomeric Arylglycosides Towards Amines. A Chemical Ionization Mass Spectrometry and Tandem Mass Spectrometry Study. J. Am. Soc. Mass Spectrom. 2004, 15, 244–252.
Donati, D.; Fusi, S.; Ponticelli, F.; Roncucci, G. Photochemical α-Cyanoethylation of Indoles. Gazz. Chim. Ital. 1994, 124, 71–76.
Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A. Jr.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Rega, N.; Salvador, P.; Dannenberg, J. J.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Cioslowski, J.; Ortiz, J. V.; Baboul, A. G.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Andres, J. L.; Gonzalez, C.; Head-Gordon, M.; Replogle, E. S.; Pople, J. A. Gaussian 98, Revision A. 11.3; Gaussian, Inc: Pittsburgh, PA.
Becke, A. D. Density-Functional Thermochemistry. III. The Role of Exact Exchange. J. Chem. Phys. 1993, 98, 5648–5652.
Beynon, J. H. In Mass Spectroscopy and Its Applications to Organic Chemistry; Elsevier: Amsterdam, 1960; p 397.
Cum, G.; Sindona, G.; Uccella, N. Effect of Substituent Group Interaction in the Fragmentation of Some Pyrrolidin-3-Ones. Org. Mass Spectrom. 1977, 12, 8–15.
Karni, M.; Mandelbaum, A. The “Even-electron Rule”. Org. Mass Spectrom. 1980, 15, 53–64.
Stagno d’Alcontres, I.; Cum, G.; Uccella, N. Electron Impact Induced Rearrangement of Organic Ions. Part II. Unimolecular Decomposition of Some Isomeric C9H10N+· Metastable Ions. Org. Mass Spectrom. 1973, 7, 1173–1177.
Author information
Authors and Affiliations
Corresponding author
Additional information
Published online January 29, 2005
Rights and permissions
About this article
Cite this article
Giorgi, G., Ponticelli, F. Structural characterization and regiochemical differentiation of α-cyanoethylindole isomers in the gas phase. J Am Soc Mass Spectrom 16, 397–405 (2005). https://doi.org/10.1016/j.jasms.2004.12.009
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1016/j.jasms.2004.12.009