2′‐Aminomethylbiphenyl‐2‐carboxylic Acid as Component of a Cyclopeptide; Crystal Structure and Conformation in Solution

The same conformation in the crystal and in chloroform (NMR data) is displayed by the biphenyl-containing cyclopeptide 1, the biphenyl units of which have S,S configuration. It can be separated chromatographically from the atropisomers, (R,S) and (R,R), also formed in the synthesis. The conformation of 1 is stabilized by two hydrogen bonds between the short peptide chains.