Synthesis of Amino Acids
Amino acids can be synthesized by various methods such as Strecker Synthesis, Gabriel phthalimide synthesis, Darapsky method, Hydantoin Method, Bucherer Hydantoin Method, Esterification, Acetylation etc. some of them are given below. These methods are frequently asked in university exams.
Strecker synthesis
Strecker synthesis is a two-step procedure for the synthesis of amino acids. It begins with the addition of cyanide ion to an imine, forming an alpha-amino nitrile followed by hydrolysis with strong acid to give an alpha-amino acid.
This method is useful for preparing glycine, alanine, serine, valine, methionine, glutamic acid, leucine, isoleucine, norleucine and phenylalanine.
Gabriel Phthalimide Synthesis
In this method, an α-halogenated acid ester is treated with potassium phthalimide to form a substituted phthalimide which on hydrolysis gives phthalic acid and an amino acid.
Darapsky Synthesis
This method involves in the condensation and simultaneous reduction of an aldehyde and cyanoacetic ester to yield an alkylcyanoacetic ester which is converted into amino acids.
Phenylalanine and tyrosine are conveniently prepared by this method.
Hydantoin Method
This method involves in the condensation of an aromatic aldehyde with hydantion followed by reduction with sodium amalgam or ammonium hydrogen sulphide and hydrolysis.
Phenylalanine, tyrosine, trypophan and methionine may be synthesized by this method.
Bucherer Hydantoin Method
This method is modified form of hydantoin method takes place by the following process-
Methionine can be prepared by this method in the following way-
