L-Alpha-methyl-DOPA from its DL-N-formyl deriv - by racemate separation with quinine and hydrolysis of the product

L-alpha-methyl-DOPA (I) is prepd. by (a) reacting DL-N-formyl-alpha-methyl-beta-(3,4-dimethoxyphenyl)alanine (II) with quinine in a polar organic solvent to form the crystalline diastereomeric (L(+)-N-formyl-alpha-methyl-beta-(3,4-dimethoxyphenyl)alanine quinine salt (III); (b) separating the crysta...

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Bibliographic Details
Main Authors KOENIG,HORST,.DR, BOELL,WALTER,.DR
Format Patent
LanguageEnglish
German
Published 04.09.1975
Edition2
Subjects
CHEMISTRY
HETEROCYCLIC COMPOUNDS
METALLURGY
ORGANIC CHEMISTRY
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Summary:L-alpha-methyl-DOPA (I) is prepd. by (a) reacting DL-N-formyl-alpha-methyl-beta-(3,4-dimethoxyphenyl)alanine (II) with quinine in a polar organic solvent to form the crystalline diastereomeric (L(+)-N-formyl-alpha-methyl-beta-(3,4-dimethoxyphenyl)alanine quinine salt (III); (b) separating the crystalline (III); (c) cleaning the salt (III), separating the quinine, and precipitating L(+)-N-formyl-alpha-methyl-beta-(3,4-dimethoxyphenyl)alanine (IV) from aq. alkaline soln. by adding acid; and (d) saponifying (IV). The product (I) is obtained in high yields and high optical purity; the diastereomeric salt (III) is obtained in pure form without recrystallisation (practically quantitative yields) and can be converted into (IV) in a yield of >90%; (II) does not undergo premature hydrolysis during the treatment.
Bibliography:Application Number: DE19742406898