title: Peptide synthesis with carbodiimide.
abstract: An isotope dilution assay for racemization during acid couplings is described and applied to carbodiimide-mediated synthesis. Using the coupling of t-BOC-L-phenylalamine with glycine derivatives as a model, racemization in solution falls in the 0.01 to  0.1% range and it is a function of reagent concentrations. A typical coupling using the solid phase method shows 0.03% racemate.
mesh_terms: D002234:Carbodiimides; D005998:Glycine; D007536:Isomerism; D010455:Peptides / Q000138:chemical synthesis*; D010649:Phenylalanine; D011865:Radioisotope Dilution Technique / Q000379:methods*
chemical_list: D002234:Carbodiimides; D010455:Peptides; D010649:Phenylalanine; D005998:Glycine