[F:1][C:2]1[CH:3]=[C:4]([C:18]#[N:19])[C:5]([C:8]2[CH:13]=[C:12]([N+:14]([O-])=O)[CH:11]=[CH:10][C:9]=2[F:17])=[CH:6][CH:7]=1>C(O)C.C(OCC)(=O)C.[Pt](=O)=O>[NH2:14][C:12]1[CH:11]=[CH:10][C:9]([F:17])=[C:8]([C:5]2[C:4]([C:18]#[N:19])=[CH:3][C:2]([F:1])=[CH:7][CH:6]=2)[CH:13]=1A suspension of 4,2′-difluoro-5′-nitrobiphenyl-2-carbonitrile (26 g, 100 mmol) in ethanol (180 ml) and ethyl acetate (180 ml) was treated with platinum(IV) oxide (1.02 g, 4.5 mmol) and then shaken under an atmosphere of hydrogen (40 psi) for 1 h. [The reaction was very exothermic and complete solution is brought about by the increase in temperature]. The catalyst was removed by filtration through glass microfibre filter paper [if any crystalline product is present the filter cake is washed with dichloromethane] and the filtrate evaporated to dryness to afford 5′-amino-4,2′-difluorobiphenyl-2-carbonitrile as a straw-coloured solid (23 g, 100%): 1H NMR (360 MHz, CDCl3) δ 3.66 (2H, s), 6.66-6.70 (1H, m), 6.71-6.74 (1H, m), 7.00 (1H, dd, J 9, 9 Hz), 7.33-7.38 (1H, m), 7.44-7.49 (1H, m).
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