Phillips-Ladenburg Benzimidazole Synthesis
The Phillips-Ladenburg benzimidazole synthesis is a name reaction in organic chemistry . It is used for the synthesis of benzimidazoles and their derivatives . It is a condensation reaction in which water is split off.
The reaction was named after the German chemist Albert Ladenburg (1842–1911) and MA Phillips.
Overview reaction
In the Phillips-Ladenburg benzimidazole synthesis, 1,2-diaminobenzene ( o- phenylenediamine) 1 reacts with the starting material 2 . The remainder of the second starting material is an alkyl group . A benzimidazole derivative is obtained as the product.
Reaction mechanism
The following mechanism is described in the literature. It is explained using the example of the condensation of 1,2-diaminobenzene with acetic acid .
The 1,2-diaminobenzene reacts with the acetic acid with elimination of water to form the diamide 3 . By adding a mineral acid, 3 reacts further to form the ammonium salt 4 , which is in equilibrium with the oxonium salt 5 . Multiple electron rearrangements then result in the formation of intermediate 6 with elimination of water . The benzimidazole derivative 7 is then formed by deprotonation .
scope of application
Benzimidazole derivatives are of great interest in pharmacy. The reason for this is that they are found in many different medical drugs. For example, they are used in drugs against cancer, coagulation disorders, inflammation, diabetes and many more.
Individual evidence
- ^ A. Ladenburg: Derivate von Diaminen In: Reports of the German Chemical Society 8, 1875, p. 677, doi: 10.1002 / cber.187500801209 .
- ↑ Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Wiley, 2010, ISBN 9780470638859 , pp. 2197-2199, doi: 10.1002 / 9780470638859 .
- ↑ D. Singh Negi, G. Kumar, M. Singh and N. Singh: Antibacterial Activity of Benzimidazole Derivatives: A Mini Review In: Research & Reviews: Journal of Chemistry 6, 2017, p. 18.
- ↑ N. Singh: Benzimidazole: A short review of their antimicrobial activities In: International Current Pharmaceutical Journal 1, 2012, p. 119.