Asymmetric synthesis of amino acids by catalytic reduction of the azlactones of substituted acylaminoacrylic acids. 4. production of (S)-tyrosine and (S)-O-methyltyrosine

Autor: Neupokoeva, E. S., Karpeiskaya, E. I., Godunova, L. F., Klabunovskii, E. I.
Zdroj: Russian Chemical Bulletin; January 1979, Vol. 28 Issue: 1 p129-135, 7p
Abstrakt: 1.The reaction of the azlactones of 4-acetoxy- and 4-methoxy-a-acetamidocinnamic acids with S-(-)-a-phenylethylamine and hydrogen in the presence of a palladium catalyst in aprotic solvents gives the a-phenylethylamides of 4-acetoxy- and 4-methoxyacetylphenylalanine with the preferred SS configuration.2.Conditions were found for the production of the pure SS-diastereomers, which give the optically pure S-tyrosine and S-O-methyltyrosine on hydrolysis.3.During the reduction of the azlactone of 4-methoxyacetamidocinnamic acid in methanol in the presence of S-(-)-a-phenylethylamine and a palladium catalyst R-(-)-N-acetyl-O-methyltyrosine methyl ester was obtained with an optical yield of 35%.4.Aminolysis of the saturated azlactones of N,O-diacetyltyrosine and N-acetyl-O-methyltyrosine by optically active S-phenylethylamine leads to a-phenylethylamides of N, O-diacetyltyrosine and N-acetyl-O-methyltyrosine with the preferred SS configuration.5.Aminolysis of the optically active azlactone of S-(-)-N,O-dxacetyltyrosine by the racemic a-phenylethylamine is accompanied by racemization, the rate of which is higher than the rate of aminolysis.6.The reductive aminolysis of the azlactones occurs mainly as reaction of the azlactone with the amine and hydrogen at the surface of the catalyst.
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