Royal Society of Chemistry View Institution's Website 1 article published in JoVE Biology Optimization of the Ugi Reaction Using Parallel Synthesis and Automated Liquid Handling Jean-Claude Bradley1, Khalid Baig Mirza1, Tom Osborne2, Antony Wiliams3, Kevin Owens1 1Department of Chemistry, Drexel University, 2Mettler-Toledo, 3Chemspider The Ugi reaction has proved to be a convenient way to quickly create diverse libraries of compounds. It involves the reaction of an amine, an aldehyde, a carboxylic acid and an isonitrile typically in methanol at room temperature. In this video, we utilize a 48-slot Mettler-Toledo MiniBlock equipped with filtration tubes and a Mettler-Toledo MiniMapper automated liquid handler was used to deliver the reagents and solvent. The parameters of interest were the concentration, the solvent composition and the excess of some of the reagents.