N,N'-(2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl)bis(4-nitrobenzamide) → N,N'-(2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl)bis(4-aminobenzamide)

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Reaction Steps

The prepared precursor, DA167, i.e., N,N′-(2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)bis(4-nitrobenzamide) (6.18 g, 0.01 mol) is dissolved in the mixture of solvents EtOH/AcOH (100/20 mL) at mild reflux. Zinc (Zn) powder (6.54 g, 0.1 mol) is carefully added in 1 portion, which is extremely exothermic, thus 2 liter (L) high-beaker is recommended to be used. The mixture is immediately bubbled up within several seconds, and then clear colorless solution is formed. The mixture is refluxed for additional 10 minutes or more and filtered hot to remove unreacted zinc. The solution is poured into H2O (300 mL), resulting in white precipitate. Precipitate is filtered and thoroughly washed with H2O (2×300 mL) by suspension-filtration procedure to remove traces of mother liquor and zinc salts. Filtration of solid and drying under vacuum at 90° C. for 12 hours yields white powder of N,N′-(2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)bis(4-aminobenzamide), DA168 4.1 g (yield 73.5%). 1H NMR 300 MHz of DA168 are as follows:

Provenance & Evidence