Di- and tripeptide segments of zervamicin II-2: Z-Thr(OBn)-Aib-N(Me)Ph and Z-Val-Aib-Hyp(OBn)-OMe

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. © 2006 International Union of Crystallography.