title: First characterization at atomic resolution of the C-activating groups in a peptide synthesis acid chloride, acid azide and carboxylic-carboxylic mixed anhydride.
abstract: The X-ray diffraction structures of three N alpha-protected, C alpha-activated MeAib derivatives are reported. They are Tos-MeAib-Cl, Tos-MeAib-N3 and Tos-MeAib-O-Piv. The geometry and conformation of these classical carboxyl activating groups, which have been characterized at atomic resolution for the first time, are discussed.
authors.affiliation: C.N.R., Department of Organic Chemistry, University of Padova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Crisma
authors.forename: V
authors.initials: V
authors.lastname: Moretto
authors.forename: G
authors.initials: G
authors.lastname: Valle
authors.forename: F
authors.initials: F
authors.lastname: Formaggio
authors.forename: C
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D000812:Anhydrides / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D011487:Protein Conformation; D014961:X-Ray Diffraction; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000812:Anhydrides; D001386:Azides; D002264:Carboxylic Acids; D002712:Chlorides; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine