Pd-1/Pd-L1 Inhibitor Impurity 6

2- (3- ((5- ((2-bromo-[1,1'-biphenyl]-3-yl) methoxy) -4-chloro-2- ((((S) -3-hydroxy-1-isopropoxy-1-oxopropan-2-yl) amino) methyl) phenoxy) methyl) pyridin-1-ium-1-yl) -3-carboxypropanoate