Fig. 2: Borax-mediated l-cyclotetrapeptide formation.
From: Production of constrained L-cyclo-tetrapeptides by epimerization-resistant direct aminolysis
a β-thiolactone synthesis. The pH values of corresponding solvent with (column 1) or without starting materials (column 2), were determined by Thermo Orion Dual Start pH/ISE Meter. The reaction yields were determined by HPLC using 6 as an external standard. Borosilicate glass was referred to Fisherbrand™ scintillation vials. b Overlaying the borax spectra before and after peptide addition in D2O. c The kinetic plot of the reaction, utilizing the equation [−ln (1−%yield)] against time at different equivalents of borax.
