The Bergmann azlactone peptide synthesis is a classic

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

process for the preparation of

dipeptide A dipeptide is an organic compound derived from two amino acids. The constituent amino acids can be the same or different. When different, two isomers of the dipeptide are possible, depending on the sequence. Several dipeptides are physiologicall ...

s. In the presence of a base,

peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

s are formed. s of N-carboxyanhydrides of

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

s with amino acid

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s (). This reaction can be looked at in further detail by Bailey. The resulting peptide is then protected by esters of benzylchroroformate in order to keep the amino groups intact (). This mechanism serves as a source of protection for the amino group in the amino acid. The ester will block the amino group from binding with other molecules. The last step in this reaction is the cyclization of the ''N''-haloacylamino acids with an acetanhydride. This will result in the expected

azlactone Oxazolone is a chemical compound and functional group, with the molecular formula C3H3NO2. It was named in-line with the Hantzsch–Widman nomenclature and is part of a large family of oxazole based compounds. There are a total of 5 structural isom ...

(). The reaction with a second amino acid allows for the ring to open, later forming an acylated unsaturated dipeptide. The reaction happens in a step-wise function which allows for the amino group to be protected and the azlactone to be produced. Catalytic

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...

and

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

then take place in order to produce the dipeptide ().J. S. Fruton, Advan. Protein Chem. V, 15 (1949); S. Archer in Amino Acids and Proteins, D. M. Greenberg, Ed. (Thomas, Springfield, IL, 1951)p 181; H. D. Springall, The Structural Chemistry of Proteins (New York, 1954) p 29; E. Baltazzi, Quart. Rev. (London) 10, 235 (1956). Cf.

References

{{Organic reactions Chemical reactions Name reactions