A Laboratory Preparation of Aspartame Analogs Using Simultaneous Multiple Parallel Synthesis Methodology

This laboratory experiment provides a unique opportunity for students to synthesize three analogues of aspartame, a commonly used artificial sweetener. The students are introduced to the powerful and useful method of parallel synthesis while synthesizing three dipeptides in parallel using solid-phase peptide synthesis (SPPS) and simultaneous multiple parallel synthesis (SMPS) methodologies. They are introduced to new concepts such as protecting groups and coupling agents and they use purification by high-pressure liquid chromatography and characterization by thin-layer chromatography, nuclear magnetic resonance, and mass spectroscopy. Over the four years we have been teaching this experiment, the students have succeeded in synthesizing the three analogues and understanding the underlying principles of SMPS and SPPS, achieving 50-70% yields of the products that were fully characterized by the aforementioned methods. The students were further assessed by an oral colloquium, their skill in the laboratory, and by a submitted report and showed a good understanding of the methodologies. (Contains 1 scheme, 1 figure, and 2 notes.)