Debus-Radziszewski imidazole synthesis

The Debus-Radziszewski imidazole synthesis is an organic reaction used for the synthesis of imidazoles from a dicarbonyl, an aldehyde, and ammonia. The dicarbonyl component is commonly glyoxal, but can also include various 1,2-diketones and ketoaldehydes. The method is used commercially to produce several imidazoles.[1] The process is an example of a multicomponent reaction.

Debus-Radziszewski imidazole synthesis
Named after Heinrich Debus
Bronisław Leonard Radziszewski
Reaction type Ring forming reaction

The reaction can be viewed as occurring in two stages. In the first stage, the dicarbonyl and ammonia condense to give a diimine (shown with unusual orientation of N-H groups):

In the second stage, this diimine condenses with the aldehyde:

This reaction is named after Heinrich Debus[2] and Bronisław Leonard Radziszewski.[3][4]

A modification of this general method, where one equivalent of ammonia is replaced by an amine, affords N-substituted imidazoles in good yields.[5]

References
  1. Ebel, K., Koehler, H., Gamer, A. O., & Jäckh, R. "Imidazole and Derivatives." In Ullmann’s Encyclopedia of Industrial Chemistry; 2002 Wiley-VCH, doi:10.1002/14356007.a13_661
  2. Debus, Heinrich (1858). "Ueber die Einwirkung des Ammoniaks auf Glyoxal". Justus Liebigs Annalen der Chemie. 107 (2): 199–208. doi:10.1002/jlac.18581070209.
  3. Radzisewski, Br. (1882). "Ueber Glyoxalin und seine Homologe". Berichte der deutschen chemischen Gesellschaft. 15 (2): 2706–2708. doi:10.1002/cber.188201502245.
  4. On the development of organic chemistry in Ukraine Dmytro O. Tymoshenko ARKIVOC 2005 (viii) 1-3 Link
  5. US patent 6,177,575, A. J. Arduengo, "Process for Manufacture of Imidazoles", issued 2001-01-23
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