title: Bioorganic stereochemistry. A study of the peptide oxazolones from Z-(Aib)n-OH (n = 2-4) in the solid state.
abstract: An investigation of the preferred conformations and modes of self-association of the peptide oxazolones from Z(-Aib-)n-OH (n = 2-4) in the solid state has been performed by infrared absorption. More detailed information on the peptide oxazolone from Z(-Aib-)3OH(2) has been obtained using X-ray diffraction. In this compound the conformations of the first two Aib residues differ substantially, only the N-terminal one being found in the usual 3(10)-(or alpha-) helical region of the Ramachandran map. The C = N-bond of the oxazolone group is not conjugated with the lactone moiety. A very weak intermolecular interaction occurs between the urethane N-H and the carbonyl group of the oxazolone ring.
mesh_terms: D000621:Aminoisobutyric Acids; D007202:Indicators and Reagents; D008958:Models, Molecular; D010080:Oxazoles; D010455:Peptides; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
chemical_list: D000621:Aminoisobutyric Acids; D007202:Indicators and Reagents; D010080:Oxazoles; D010455:Peptides