Pyaop reagent156311-83-0100 % similar Pybop128625-52-568 % similar Bop reagent56602-33-645 % similar O-(Benzotriazol-1-yl)-N,N,N',N'-bis(tetramethylene)uronium Hexafluorophosphate105379-24-641 % similar 1-Hydroxy-7-azabenzotriazole39968-33-738 % similar