1,1'-(4,4'-Biphenylylenebis(2-oxoethylene))bis(1-methylpiperidinium dibromide) 15172-85-7 4,4'-Bis(piperidinoacetyl)biphenyl dimethiobromide Piperidinium, 1,1'-(4,4'-biphenylylenebis(2-oxoethylene))bis(1-methyl-, dibromide