• University of Texas

• CH 320N

Draw the product formed when alanine is treated with the following reagents. You need not worry about stereochemistry! a. Aqueous NaOH b. Aqueous HCl c. Ethanol and sulfuric acid Quiz Amino Acids -- Reactions •Electrophoretic purification (done) •Ninhydrin-based detection (done) •N-protection/deprotection •C-protection/deprotection •Coupling to form peptides •Use of Merrifield resin to control and facilitate coupling These relate to issue of peptide synthesis The Peptide Problem: Linking 2 Amino Acids Gives a Dipetide, 3, a Tripeptide, 4, a Tetrapeptide, etc. In other words, simple condensation gives a terrible mixture! If our desire is to get serylalanine or another dipeptide, we need a so-called rational synthesis. Use selective protection and coupling of the requisite amino acids. N-protection There are two Common Ways, Both of Which involve Carbamates: 1. Benzyloxycarbonyl (“carbobenzoxy”; “Cbz”, or just “Z” for short) 2. t-Butoxycarbonyl (“t-BOC” or just “BOC” for short) N-deprotection Both Cbz and BOC prot