P(Br)(Br)[Br:2].[F:5][C:6]1[CH:7]=[C:8]([CH2:16]O)[CH:9]=[C:10]([F:15])[C:11]=1[N+:12]([O-:14])=[O:13].CO.C([O-])(O)=O.[Na+]>CCOCC>[Br:2][CH2:16][C:8]1[CH:9]=[C:10]([F:15])[C:11]([N+:12]([O-:14])=[O:13])=[C:6]([F:5])[CH:7]=1To a solution of PBr3 (7.04 mL, 73 mmol) in Et2O (200 mL) is added under argon at 0° C. a solution of (3,5-difluoro-4-nitro-phenyl)-methanol (9.3 g, 48.7 mmol) in Et2O (200 mL). The reaction mixture was allowed to warm to 25° C. and stirred for 24 h at 25° C. After the addition of MeOH (5 mL) at 0° C., the reaction mixture was poured onto cold aq. NaHCO3 solution and the product was extracted with EtOAc. Combined organic extracts were washed with saturated NaHCO3 solution and brine, dried over MgSO4, filtered and concentrated to provide the title compound after filtration through a plug of silicagel with hexane-EtOAc 3:1 as a yellow solid: TLC (hexane-EtOAc 3:1) Rf=0.40; HPLC RtA=2.01 min; 1H NMR (400 MHz, CDCl3): δ 7.14 (d, 2H), 4.40 (s, 2H).
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