Patent ID: 7193103

Claim:
A process of synthesizing N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine 1-methyl ester comprising the steps of: (a) reacting an admixture of (i) N-(3,3-dimethylbutyl)-L-aspartic acid and (ii) a ketone or an acetal of a ketone in a first solvent for a time and at a temperature sufficient to produce an oxazolidinone derivative having the formula wherein R 1 is R 2 ; R 2 is Ph or CX 3 ; and X is H, Cl, Br or F; and (b) reacting an admixture of the oxazolidinone derivative and L-phenylalanine or L-phenylalanine methyl ester in a second solvent for a time and at a temperature sufficient to produce N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine 1-methyl ester, wherein the first solvent and the second solvent are different.