| 摘要 |
L - a - methyl - b - (3,4 - dihydroxyphenyl) alanine is prepared by reacting 2-phenyl-4-methyl - 5 - oxazolinone in the form of a metal salt or in the presence of a basic condensing agent for forming such a salt with a reactive ester of veratryl alcohol to form 2-phenyl - 4 - veratryl - 4 - methyl - 5 - oxazolinone, partially hydrolysing this to N-benzoyl-a -methyl - b - (3,4 - dimethoxyphenyl)alanine, resolving this to separate the L-enantiomer thereof, and hydrolysing this. Resolution may be effected, for example, with brucine, quinine, quinidine or codeine. Para-toluenesulphonic acid veratryl ester is prepared from sodium p-toluenesulphonate and veratryl chloride or p-toluene sulphonyl chloride and veratryl alcohol. |
