Highly efficient coupling reagents - phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl
ester, diphenylphosphinic acid 2-phenylbenzimidazol-1-yl ester and phosphoric acid
diphenyl ester 2-phenylbenzimidazol-1-yl ester - were designed, synthesized and successfully
applied in peptide coupling reactions. Their efficiency was evaluated through the
synthesis of a range of amides and peptides, and the extent of racemization was studied
by HPLC and found to be negligible. The mechanism of action is probably similar to
those found for organophoshorus esters of hydroxybenzotriazole: a presumption supported
by the isolation and characterization by mass spectrometry and 1H NMR of some of the proposed intermediates.
N-hydroxy-2-phenylbenzimidazole - peptide coupling reagents - HOBt - amide synthesis
- minimal racemization