The Preparation And Analysis Of α-phenylethylamine

The preparation of enantiomer is essential important for their disaffinity of bioactivity, toxicity and the mechanism of metabolizability. Optically active α-phenylethylamine is one of important intermediates. It is important to preparate and analyse α-phenylethylamine, because it is one reagent when resoluting racemic body and material in asymmetric synthesis. The seperation of enantiomer by both chemical derivation and high performance liquid chromatography (HPLC) on chiral stationary phases (CSP) have been thought of as effective approaches.In this paper, R-α-phenylethylamine and S-α-phenylethylamine are prepared with a type of facile reagent called R(-)TTCA by chemical derivation. All reaction ratios and conditions were studied and high productivity of. To solve the problem N2 protection and reducer were used. Other impurities were removed from R(-)TTCA via recrystal and column chromatography to get colorless crystal in the shape of pin whose yield is 75%, [α] D22 is -93.5o, melting point is 183.0～184.5℃. R, S- α- phenylethylamine can be separated into a pair of enantiomer by R(-)TTCA in which S-α-phenylethylamine and R-α-phenyl- ethylamine are included. The purity of S-α- phenylethylamine is 89.61%, [α] D23=-27.78o(c=0.306, C2H5OH); The yield of R-α-phenylethylamine is 92.5%, the purity is 97.23%, [α] D23=+30.14o(c=0.365,C2H5OH). In the paper another method to prepare α- phenylethylamine with optics activity by inducing crystal is studied. S-α- phenylethylamine and R-α- phenylethylamine that have been separated by R(-)TTCA react with cinnamonic acid individually on certain condition to get seed crystal. Then the seed crystal is used to induce salt of singleness enantiomer from racemic cinnamate which is processed to obtain pure singleness enantiomer. The yield of S-α-phenyl ethylamine is 82.6%, the purity is 88.54%, [α] D25=-27.45o(c=0.255,C2H5OH); the yield of R-α-phenylethylamine is 79.7%, the purity is 95.10%, [α] D25=+29.48o(c=0.458,C2H5OH).The appliance of Pirkle's chiral stationary phases of HPLC is also presented in the paper. According to chiral resolution mechanism and chemical structure of Prikle's CSP, a chiral substance of new amide style called 5-(11-undecenethy-lamido)–phenylethylamine derived from R, S-α- phenylethylamine has been produced. There is no paper on HPLC resolution of 5-(11-undecenethy- lamido)-phenylethylamine. It is separated by DNB-Leucine CSP of HPLC in the experiment. And the influence of the makeup of mobile phases to the retaining time of solute staying in chromatographic column and degree of separation between solute are studied. Then we got the HPLC condition that α is 1.10, which usually furnishes both enantiomers in high optical purity. The method can be used as analysis, which solve the inaccuracy problem when using polarimeter instrument to determine the optical rotation of enantiomer, etc.