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Weidenhagen Synthesis

(Weidenhagen Reaction, Weidenhagen Imidazole Synthesis)

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr659

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Weidenhagen Synthesis. Comprehensive Organic Name Reactions and Reagents. 659:2951–2955.

Publication History

  1. Published Online: 15 SEP 2010

Abstract

This reaction is a modification of the Radziszewski reaction for the synthesis of imidazoles via the treatment of the mixture of α-hydroxy ketones, aldehydes, and ammonia with cupric acetate followed by hydrogen sulfide or sodium sulfide and is known as the Weidenhagen modification as well as the Weidenhagen synthesis. The study finds that the excess cupric acetate can complex with the resulting imidazole to form a water-insoluble precipitate and some imidazoles are found not to complex with cupric ion, such as 2-chlorobenzimidazole. Overall, due to the low yield of this reaction and laborious procedures, this reaction has not been popularly used in the preparation of imidazole derivatives until recently.

Keywords:

  • 4(5)-hydroxymethylimidazole;
  • cupric acetate;
  • imidazole;
  • α-hydroxy ketones