Cyanamides peptide synthesis with

Cyanamide, NsC—NH, in the tautomeric form HN==C=NH, is a carbodiimide and can be used in peptide synthesis. Diethylcyanamide, although incapable of tau-tomerism, functions as a dehydrating agent for the coupling of an N-protected amino acid with an amino acid ester. Best yields are obtained by heating the three components without solvent at 100° for 2 hrs. 

---