5-Fluoro-3-methyl-2-nitro-phenylamine (0.97 g, 5.7 mmol), 4-N-BOC-aminopiperidine (1.60 g, 8.0 mmol), diisopropylethylamine (2.5 ml, 14 mmol) and DMSO (10 ml) are combined and stirred at 85° C. for 3 hours. The reaction mixture was poured on saturated aqueous NaHCO3 solution and extracted with ethyl acetate. The organic layers were washed with water (3×) and brine, dried over Na2SO4 and concentrated. Flash column chromatography on silica (eluent hexanes-ethyl acetate-triethylamine 50-50-1, then 33-66-1) gave the title compound as a yellow solid. (1.57 g, 79%). LCMS (M+H)+ m/z 351 (t=1.55 min.). 1H NMR (500 MHz, CD3OD) δ 6.70 (1H, broad s), 6.22 (1H, d, J=2.5 Hz)), 6.13 (1H, d, J=2.5 Hz), 3.88 (2H, d, J=13.3 Hz), 3.58 (1H, broad s), 2.98 (2H, t, J=11.8 Hz), 2.48 (3H, s), 1.92 (2H, J=11.3 Hz), 1.48 (2H, m), 1.45 (9H, s).
