Abstract
The title compounds, O-benzyl-N-(benzyloxycarbonyl)threonyl-2,N-dimethylalaninanilide, C30H35N3O5, and methyl (4R)-4-benzyloxy-N-(benzyloxycarbonyl)valyl-2-(methylalanyl)prolinate, C30H39N3O7, were obtained from the `azirine coupling' of the corresponding protected amino acids with 2,2,N-trimethyl-2H-azirin-3-amine and methyl (4R)-4-(benzyloxy)-N-(2,2-dimethyl-2H-azirin-2-yl)prolinate, respectively. The Aib unit in each molecule has the greatest turn- or helix-inducing effect on the molecular conformation. Intermolecular N—H⋯O interactions link the molecules of the tripeptide into sheets and those of the dipeptide into extended chains.
Linden, Anthony