Crystal structure of N-(tert-but­oxy­carbon­yl)glycyl-(Z)-β-bromo­dehydro­alanine methyl ester [Boc–Gly–(β-Br)^(Z)ΔAla–OMe]

In a de­hydro­amino acid with a C=C bond between the α- and β-C atoms, the amino acid residues are linked trans to each other and there are no strong intra­molecular hydrogen bonds. The torsion angles indicate a non-helical conformation of the mol­ecule.

Crystal structure of N-(tert-but­oxy­carbon­yl)phenyl­alanylde­hydro­alanine isopropyl ester (Boc–Phe–ΔAla–OiPr)

In the crystal structure of the de­hydro­dipeptide (Boc-Phe-ΔAla-OiPr), the mol­ecule has a trans configuration of the N-methyl­amide group. Its geometry is different from saturated peptides but is in excellent agreement with other de­hydro­alanine compounds. In the crystal, an N—H...O hydrogen bond links the mol­ecules in a herringbone packing arrangement.