Crystal structures of a D‐residue containing tetrapeptides 1. tert‐Boc‐D‐Valyl‐alanyl‐leucyl‐alanyl methoxide, butanol solvate

The crystal structure of a heterochiral peptide, viz. Boc-D-Val-Ala-Leu-Ala-OMe, with a D-residue in the beginning of the sequence has been determined (a= 9.464(5), b= 35.615(5), c= 9.703(2) A, space group P21212, Z= 4, R= 0.09). The peptide is in the extended β-conformation and the packing is stabilised by four N—H. O hydrogen bonds in an antiparallel β-sheet arrangement. The solvent molecule is disordered and does not have any specific interactions with the peptide.