title: Delay of coupling caused by excess additives.
abstract: Use of excess quantity of additives such as 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole, or 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine could retard carbodiimide-mediated peptide coupling or aminolysis of the active esters in organic solvents generally employed in peptide chemistry. Solubility test and infrared spectroscopic data suggested that the amine components interacted with the additives to form some aggregates, which were less reactive toward acylation. The use of 0.1 equimolar additives against carboxyl components or carbodiimides was advantageous for rapid and efficient coupling reaction, especially when the carboxyl components were amino acids carrying urethane type N-protecting groups.
authors.affiliation: Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, 350-0295, Japan. nozakis@josai.ac.jp
authors.forename: Sukekatsu
authors.initials: S
authors.lastname: Nozaki
mesh_terms: D000588:Amines / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D012995:Solubility; D012997:Solvents; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
chemical_list: D000588:Amines; D007202:Indicators and Reagents; D010455:Peptides; D012997:Solvents