IC50: Not available.

PyBOP (benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate), the analog of BOP where dimethylamino groups are replaced with pyrrolidino, is a peptide coupling reagent used in solid phase peptide synthesis. As the only analog of BOP which shows equivalent properties in peptide bond formation, PyBOP is widely used as a substitute for the BOP, with the aim of avoiding formation of hexamethylphosphoric triamide (HMPA) which is a carcinogenic side product. After being extensively reported with toxicity, HMPA has been recently included in the “Seveso list” of dangerous chemicals. Both in solution and in solid phase peptide synthesis, BOP performs as an excellent peptide coupling reagent. However, formation of HPMA couldn’t be avoided during the manufacture and utilization of BOP. [1]

In vitro: Under the same condition to that of BOP, coupling tests were conducted using PyBOP as coupling reagent. In the DCM molar solution containing N-protected amino acid, compounds were added as follow: coupling reagent, C-protected amino acid hydrochloride and DIEA. An immediate reaction could be then noticed by TLC monitoring, even in the case of hindered amino acids. Moreover, the magnitude of racemization seemed to be 50% lower than that obtained with BOP in the Young’s test, and exhibited superiority in the Anteunis’ test. [1]

In vivo: So far, no in vivo data has been reported.

Clinical trial: So far, no clinical trial has been conducted.

Reference:
[1]Coste J, Le-Nguyen D and Castro B.  PyBOP@: A new peptide coupling reagent devoid of toxic by-product. Tetrahedron Lett. 1990 Mar; 31(2): 205-8.