N-[tert-Butoxy­carbonyl­glycyl-(Z)-α,β-de­hydro­phenyl­alanyl­glycyl-(E)-α,β-de­hydro­phenyl­alanyl]­glycine methyl ester dihydrate

The title pentapeptide, Boc⁰—Gly¹–Δ^ZPhe²—Gly³–Δ^EPhe⁴—Gly⁵—OMe, C₃₀H₃₅N₅O₈·2H₂O, adopts the type I β-turn conformation for the Δ^ZPhe²—Gly³ residues. It is stabilized by a intramolecular hydrogen bond between the Δ^EPhe⁴ NH and Gly¹ CO groups. All the amino acid residues in the pentapeptide sequence are linked trans to each other. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.