Product in indole detection by Ehrlich's reagent.

Abstract

Ehrlich's reagent (p-dimethylaminobenzaldehyde [DMAB, 1] in 95% EtOH with HCl as catalyst) was employed in spot tests of indoles, providing a diagnosis of, for example, liver diseases, hemolytic processes, occlusion of the common bile duct, and carcinoid syndrome. Although the reagent has been widely used for more than a century, it is not clear how many indole molecules react with a DMAB molecule and whether the reaction takes place at the α- or β-position of the indole molecule. Research here shows that the reaction of DMAB (1) with indole (2) in a 1:2 ratio gives β-bis(indolyl)methane (3). The reaction occurs at the β-position of indole under the conditions of the Ehrlich test, as confirmed by the crystal structure of 3.

• Authors: Adam C Lamb, Roberto A Federico-Perez, Zi-Ling Xue
• Journal: Analytical biochemistry (Anal Biochem) Vol. 484 Pg. 21-3 (Sep 01 2015) ISSN: 1096-0309 [Electronic] United States
• PMID: 25958008 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical References

• Benzaldehydes
• Indoles
• indole
• p-dimethylaminobenzaldehyde

Topics

• Benzaldehydes (chemistry)
• Indoles (analysis, chemistry)
• Models, Molecular
• Molecular Conformation