4-Amino-1,2-dithiolane-4-carboxylic acid (Adt) as cysteine conformationally restricted analogue. synthetic protocol for Adt containing peptides

An efficient and versatile protocol to incorporate the achiral and Cα,α-tetrasubstituted 4-amino-1,2-dithiolane-4-carboxylic acid Adt (1) residue into peptides is described. The 2,2-bis[(benzylthio)methyl]glycine N-carboxy anhydride (5) was found to be the key reactive intermediate from which both Boc-Adt-OMe (8) and the glutathione analogue H-Glu(-Adt-Gly-OH)-OH (12) can be obtained.