O-(Benzotriazol-1-yl)-N,N,N',N'-bis(tetramethylene)uronium Hexafluorophosphate105379-24-6100 % similar Pybop128625-52-557 % similar Bop reagent56602-33-650 % similar Pyaop reagent156311-83-041 % similar N,N,N',N'-Tetramethyl-O-(3,4-dihydro-4-oxo-1,2,3-benzotriazin-3-yl)uronium tetrafluoroborate125700-69-833 % similar