[Br-].[F:2][CH2:3][CH2:4][N+:5]1[CH:10]=[CH:9][C:8]([C:11]2[CH:16]=[CH:15][C:14]([N+:17]([O-:19])=[O:18])=[C:13]([O:20][CH3:21])[CH:12]=2)=[CH:7][CH:6]=1.[BH4-].[Na+].CCOC(C)=O>CO>[F:2][CH2:3][CH2:4][N:5]1[CH2:6][CH:7]=[C:8]([C:11]2[CH:16]=[CH:15][C:14]([N+:17]([O-:19])=[O:18])=[C:13]([O:20][CH3:21])[CH:12]=2)[CH2:9][CH2:10]1To 1-(2-fluoroethyl)-4-[3-(methyloxy)-4-nitrophenyl]pyridinium bromide (2.0 g, 5.6 mmol) in MeOH (10 mL) cooled in an ice bath was added NaBH4 (1.1 g, 28 mmol) at such a rate to control the foaming which occurred. The mixture was stirred for 2 h then rotovaped down. EtOAc (200 mL) was added, and the solution was washed with saturated NaHCO3 solution and H2O. The solution was dried (MgSO4), filtered, rotovaped and purified by silica gel chromatography. The desired fractions were combined and rotovaped to give the title compound of step B (0.90 g, 3.2 mmol, 57%) as an oil. 1H NMR (400 MHz, CDCl3) δ 7.86 (d, J=8.4 Hz, 1H), 7.05-7.00 (m, 2H), 6.22-6.18 (m, 1H), 4.73 (dd, J=5.1, 4.8 Hz, 1H), 4.61 (dd, J=5.1, 4.8 Hz, 1H), 3.97 (s, 3H), 3.36-3.31 (m, 2H), 2.94-2.82 (m, 4H), 2.65-2.57 (m, 2H).
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