The synthesis of 4-nitro-4'-biphenylcarboxylic acid (intermediate in the preparation of V) was accomplished through the following series of reactions: $-toluidine--+ 4-methylbipheny14--+ 4-methyl-4'-nitrobiphenyl--+ 4-nitro-4'-biphenylcarboxylic acid. 5 The preparation of 5, 5'- dinitrodiphenic acid (used in the preparation of IV) was first effected by Pufah16 in the following manner: 4-nitro-2-aminobenzoic acid-+ 4-nitro-2-iodobenzoic acid--+ methyl ...
[Rewcastle, Gordon W.; Atwell, Graham J.; Baguley, Bruce C.; Calveley, Stephen B.; Denny, William A. Journal of Medicinal Chemistry, 1989 , vol. 32, # 4 p. 793 - 799]
