- Schotten-Baumann reaction
The Schotten-Baumann reaction is a method to synthesise
amide s fromamine s andacid chloride s:Sometimes the name for this reaction is also used to indicate the reaction between an acid chloride and a
alcohol to form anester . The reaction was first described in 1883 by Germanchemist sCarl Schotten andEugen Baumann [W Pötsch. "Lexikon bedeutender Chemiker" (VEB Bibliographisches Institut Leipzig, 1989) (ISBN 3-323-00185)] [M B Smith, J March. "March's Advanced Organic Chemistry" (Wiley, 2001) (ISBN 0-471-58589-0)] .Reaction mechanism
In the first step an acid chloride reacts with an amine so that an amide is formed, together with a proton and a chloride ion. Addition of a base is required to absorb this acidic proton, or the reaction will not proceed. Often, an aqueous solution of a base is slowly added to the reaction mixture.
The name "Schotten-Baumann reaction conditions" is often used to indicate the use of a two-phase solvent system, consisting of water and an organic solvent. The base within the water phase neutralizes the acid, generated in the reaction, while the starting materials and product remain in the organic phase, often
dichloromethane ordiethyl ether .Applications
The Schotten-Baumann reaction or reaction conditions are widely used today in
organic chemistry . Examples include:* synthesis of N-vanillyl nonanamide, also known as synthetic
capsaicin
* synthesis ofbenzamide frombenzoyl chloride and aphenethylamine
*acylation of abenzylamine withacetyl chloride (acetic anhydride is an alternative)
* in the Fischer peptide synthesis (Hermann Emil Fischer , 1903) [cite journal
author = Emil Fischer
title = Synthese von Polypeptiden
year = 1903
journal =Berichte der deutschen chemischen Gesellschaft
volume = 36
issue = 3
pages = 2982-2992
doi = 10.1002/cber.19030360356 ] [ [http://www.drugfuture.com/OrganicNameReactions/ONR135.htm Fischer Peptide Synthesis ] ] an α-chloro acid chloride is condensed with theester of anamino acid . The ester is then hydrolyzed and the acid converted to the acid chloride enabling the extension of thepeptide chain by another unit. In a final step the chloride atom is replaced by an amino group completing thepeptide synthesis .References
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