PyAOP ((7-Azabenzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate) is a reagent used to prepare amides from carboxylic acids and amines in the context of peptide synthesis.

[2] It is a derivative of the HOAt family of amide bond forming reagents.

It is preferred over HATU, because it does not engage in side reactions with the N-terminus of the peptide.

[3] Compared to the HOBt-containing analog PyBOP, PyAOP is more reactive due to the additional nitrogen in the fused pyridine ring of the HOAt moiety.

[4] Thermal hazard analysis by differential scanning calorimetry (DSC) shows PyAOP is potentially explosive.