title: Efficient peptide coupling involving sterically hindered amino acids.
abstract: Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-alpha-aminoacyl)benzotriazoles with amino acids, wherein at least one of the components was sterically hindered, to provide compounds 3a-e, (3c +3 c'), 5a-d, (5a + 5a'), 6a-c, (6b + 6b'), 8a-c, 9a-e, 10a-d, and (10a + 10a') in isolated yields of 41-95% with complete retention of chirality as evidenced by NMR and HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of sterically hindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixtures or racemates; compound numbers without brackets represent enantiomers.).
authors.affiliation: Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA. katritzky@chem.ufl.edu
authors.forename: Alan R
authors.initials: AR
authors.lastname: Katritzky
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Todadze
authors.forename: Parul
authors.initials: P
authors.lastname: Angrish
authors.forename: Bogdan
authors.initials: B
authors.lastname: Draghici
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D010455:Peptides