The Synthesis And Study Of L-homophenylalanine

L-homophenylalanine is a kind of non-natural chiral amino acids, this kind of amino acid and its ester was important intermediates which was synthesized with angiotensin converting enzyme inhibitor class treatment for hypertension and congestive heart failure drug. It has the very good application prospect, For this reason, many methods for the preparation of L-homophenylalanine have been developed, such as chemical and enzymatic and microbiological syntheses. However, there is no practical method with the potential for largr scale processing. and therefore the synthesis method has very important significance.By consulting relevant literatures,summarizing the advantages and disadvantages of synthetic routes, the final choice is that L-homophenylalanine ethyl ester hydrochloride was prepared from the readily available L-malic acid by a six-step way. The synthesis of (S)-a-acetoxybutanedioic anhydrous was completed by acetylation-dehydration with acetyl chloride, The (S)-2-hydroxy-4-oxo-4-phenylbutanoic acid was obtained from the Friedel-Crafts reaction of (S)-α-acetoxybutanedioic anhydrous with anhydrous benzene, Hydrogenolysis of (S)-2-hydroxy-4-oxo-4-phenylbutanoic acid over10%palladium charcoal afforded (S)-2-hydroxy-4-phenybutanoic acid, Finally, the target product was prepared from esterification reaction and replaced by sodium azide. There is no hydroxyl protection or separation, or the use of highly-contaminated halide reagents in this method. The route reduced environmental pollution and simplified the steps. The process of reaction was optimized. In the reduction step,Make use of the catalytic hydrogenation method, the yield was achieved80%, the reaction time was reduced by half. In the reduction step of azido, Make use of the catalytic ammonium chloride and zinc power, the yield was achieved93%. The total yield was improved to48.1%.The structure of the synthetic products were characterized by measuring melting point, mass spectra(MS) and1H nuclear magnetic resonance(NMR). The results proved:the structures and performance indexes of the products conformed to the designed requirement, this can prognosticate the synthesis design of using the original raw material L-malic acid, the total synthesis was practical and effective.