170950-56-8 2-Butenoic acid, 4-(2',4'-difluoro(1,1'-biphenyl)-4-yl)-2-methyl-4-oxo- 4-(2',4'-Difluoro(1,1'-biphenyl)-4-yl)-2-methyl-4-oxo-2-butenoic acid 4-(2',4'-Difluorobiphenyl-4-yl)-3-methyl-4-oxobutanoic acid