Process for the preparation of .alpha.-L-aspartyl-L-phenylalanine alkyl esters
AssigneeMonsanto Company
InventorsGerald L. Bachman, Marvin L. Oftedahl, Billy D. Vineyard
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Abstract
A process for the preparation of .alpha.-L-aspartyl-L-phenylalanine alkyl esters wherein L-phenylalanine is reacted with N-protected-L-aspartic anhydride, the resulting product is treated to yield .alpha.-L-aspartyl-L-phenylalanine which is esterified with an alkanol to yield an .alpha.-L-aspartyl-L-phenylalanine alkyl ester which is recovered. Novel precursors for .alpha.-L-aspartyl-L-phenylalanine alkyl esters are prepared in the process of this invention.
Claims14
A process comprising reacting an N-protected-L-aspartic anhydride with L-phenylalanine to form N-protected-.alpha.-L-aspartyl-L-phenylalanine wherein the N-protecting group is selected from the group consisting of formyl, acetyl, benzoyl, substituted and unsubstituted carbobenzoxy, t-butoxycarbonyl and the hydrohalide salts, removing the protecting group from the N-protected-.alpha.-L-aspartyl-L-phenylalanine to form .alpha.-L-aspartyl-L-phenylalanine and esterifying the .alpha.-L-aspartyl-L-phenylalanine with an alkanol having from 1 to 3 carbon atoms to form the corresponding .alpha.-L-aspartyl-L-phenylalanine alkyl ester which is recovered.
A process comprising reacting N-formyl-aspartic anhydride with l-phenylalanine in glacial acetic acid to form N-formyl-.alpha.-L-aspartyl-L-phenylalanine, removing the formyl group from N-formyl-.alpha.-L-aspartyl-L-phenylalanine by hydrolysis with an aqueous solution of hydrogen chloride and esterifying the resulting .alpha.-L-aspartyl-L-phenylalanine with methanol in the presence of hydrogen chloride to form .alpha.-L-aspartyl-L-phenylalanine methyl ester and recovering the .alpha.-L-asparatyl-L-phenylalanine methyl ester.
N-protected- .alpha.-L-aspartyl-L-phenylalanine.
N-formyl-.alpha.-L-aspartyl-L-phenylalanine.
Dependencies are inferred from the claim text.