The peptideZ-Aib-Aib-Aib-L-Ala-OtBu

Abstract

The title peptide,N-benzyloxycarbonyl-α-aminoisobutyryl-α-aminoisobutyryl-α-aminoisobutyryl-L-alaninetert-butyl ester orZ-Aib-Aib-Aib-L-Ala-OtBu (Aib is α-aminoisobutyric acid,Zis benzyloxycarbonyl and OtBu indicates thetert-butyl ester), C27H42N4O7, is a left-handed helix with a right-handed conformation in the fourth residue, which is the only chiral residue. There are two 4→1 intramolecular hydrogen bonds in the structure. In the lattice, molecules are hydrogen bonded to form columns along thecaxis.