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Aspartame comes under the category of artificial sweeteners. It is employed as a replacement for sugar in several food items and is sweeter than sugar.

The steps involved in the synthesis of aspartame can be given as:

• In the first step, the amino group of aspartame is to be protected by using di-tert-butyl-dicarbonate.
• In the second step, the carboxyl group of aspartame is activated by DCCD. So, this N-protected and activated carboxyl group Leucine reacts with phenyl alanine and forms the dipeptide Asp-Phe.
• In the third step, the carboxyl group of N-protected Aspartate reacts with the methyl ester of phenyl alanine to form the methyl ester of dipeptide Asp-Phe.

Then, the protected group on N-terminal is removed by trifluoroacetic acid, which is shown as:

Synthesis of aspartame using DCCD