Amino acid heptyl (Hep) esters are accessible as generally protected dipeptides the N- terminal protecting groups are crystalline hydro tosylates 3 from the amino acids by azeo- cleaved by chemical methods without affecting the Hep esters. tropic esterification with 1- heptanol in high yields. They can On the other hand, the heptyl esters can be hydrolyzed uqder be condensed with Z-, Boc-, and Aloc-protected amino acids mild conditions (pH= ...
