METHOD OF PREPARING ÑÔ-SUBSTITUTED-N-CARBOBENZOXY-L-ASPARATATE

摘要

The beta-substd.-N-carbobenzoxy-L-aspartate (β-substd. NCA) of formula (I) [R= methyl or benzyl is produced by (a) dissolving a beta-substd.-N- benzyloxycarbonyl-aspartic acid of formula (II) [R= methyl or benzyl in an anhydrous benzne, (b) adding a phosphorus pentaoxide (PO5) to the soln., (c) agitating the mixt., (d) adding an anhydrous petroleum ether to it to obtain a precipitate, and filtering the precipitate and drying it at the room temperature. The cpd. (I) is useful as a precursor for the mfr. of an L-alpha-aspartyl-L- phenylalanine methyl ester (aspartame).