Studies on racemization associated with the use of benzotriazol-1-yl-tris (dimethylamino)phosphonium hexafluorophosphate (BOP).
The influence of the amount and nature of the necessary tertiary amine on racemization attending the BOP-mediated coupling of N-benzyloxycarbonylglycyl-dipeptides has been examined by determining the epimeric products by high-performance liquid chromatography. Racemization was encountered in all cases examined that included dichloromethane as solvent. The least racemization occurred when the base was diisopropylethylamine, the most when the base was N-methylmorpholine. Excess base promoted racemization. Racemization was significantly diminished but not eliminated when 1-hydroxybenzotriazole was added to the reaction mixtures. The above results pertain to the coupling of peptide segments; they do not pertain to the coupling of N-alkoxycarbonylamino acids.
Steinauer
R
R
Department of Biochemistry, University of Ottawa, Ontario, Canada.
Chen
F M
FM
Benoiton
N L
NL
D000588:Amines / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds; D013237:Stereoisomerism
D000588:Amines; D007202:Indicators and Reagents; D009943:Organophosphorus Compounds; C031032:benzotriazol-1-yloxy-tris(dimethylamino)phosphonium