The Elusive Antiaromaticity of Maleimides and Maleic Anhydride: Enthalpies of Formation of N-Methylmaleimide, N-Methylsuccinimide, N-Methylphthalimide, and N-Benzoyl-N-methylbenzamide

  • J Org Chem. 1997 May 2;62(9):2732-2737. doi: 10.1021/jo9621985.
María Victoria Roux  1 ,  Pilar Jiménez ,  Maria Ángeles Martín-Luengo MÁ ,  Juan Z. Dávalos ,  Zhiyuan Sun ,  Ramachandra S. Hosmane ,  Joel F. Liebman
Affiliations
  • 1. Institute of Physical Chemistry "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain, and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250.
PMID: 11671632 DOI: 10.1021/jo9621985
Abstract

In order to understand the antiaromaticity of maleimides, the enthalpies of formation and sublimation of N-methylmaleimide, N-methylsuccinimide, N-methylphthalimide, and N-benzoyl-N-methylbenzamide were measured. The numerical values of enthalpies of formation for these compounds in the solid state are -329.3 +/- 1.4, -469.8 +/- 1.6, -325.0 +/- 2.1, and -239.6 +/- 3.8 kJ mol(-)(1), respectively, while the corresponding values in the gaseous state are -256.0 +/- 1.5, -389.7 +/- 1.6, -233.9 +/- 2.2, and -119.5 +/- 3.8 kJ mol(-)(1), respectively. The values of enthalpies of sublimation for the same compounds are 73.3 +/- 0.5, 80.1 +/- 0.3, 91.1 +/- 0.5, and 120.1 +/- 0.4 kJ mol(-)(1), respectively. We find that the antiaromaticity of maleimides is only modest.

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