The Synthesis Of Dl-phenylalanine And Split

Phenylalanine, a -amino - P -phenylpropionic acid, include DL- phenylalanine, L-phenylalanine, D- phenylalanine, is a kind of amino acid. L-phenylalanine can be used to synthesis new medicament and sweetener. D-phenylalanine has analgesic activity.The technological conditions of the synthesis of DL-phenylalam'ne by using phase transfer catalyst (PTC) and others are discussed . The original material is glycine. The synthetical steps are as follows: esterification, aldimination, alkylation and hydrolysis. The total yield has reached 52.3%.A resolution of DL -phenylalanine is carried out via formation of a optically active salt with L(+)-tartaric acid in methanol. When the salt reacted with aqueous NaOH, optically active L- phenylalanine (e.e.=58.9%) and D- phenylalanine (e.e.=70%) are separated.The L-phenylalanine and D- phenylalanine can be prepared in high optical purity by treating N-acetylphenylanine in water using free aminoacylase as a catalyst. A number of influencing factors to the resolution reaction are discussed, include pH value, reaction temperature, amount of aminoacylase, concentration of substrate and Co2+. In end. L-phenylalanine is obtained with 98.8% optical purity in 70.3% yield, D- phenylalanine can be obtained with 96% optical purity in 63% yield.The racemic percentages of L- phenylalanine under different conditions (temperature. pH value) is compared and the racemic regularity is discussed from structural theory.