Reaction Steps
A solution of the chloride 21 (2.0 g, 9.0 mmol), 2-(3-methoxy-1-piperidinyl)ethylamine (283) (1.8 g, 11.4 mmol) and Et3N (1.5 mL, 9.9 mmol) in DME (140 mL) was stirred at reflux temperature for 22 h. The solution was cooled to 20° C., the solvent evaporated and the residue purified by chromatography, eluting with 5% MeOH/DCM to give (i) starting material 21 (0.6 g, 30%) and (ii) 1-oxide 40 (1.9 g, 61%) as a yellow solid: mp 123-124° C.; 1H NMR δ 8.07 (s, 1H, H-9), 7.39 (s, 1H, H-5), 5.81 (br s, 1H, NH), 3.54-3.58 (m, 2H, CH2N), 3.35 (s, 3H, OCH3), 3.24-3.31 (m, 1H, CHO), 2.97-3.03 (m, 5H, H-6, H-8, CH2), 2.68-2.74 (m, 1H, CH2), 2.63 (dt, J=6.1, 2.4 Hz, 2H, CH2N), 2.14 (p, J=7.4 Hz, 2H, H-7), 1.96-2.07 (m, 3H, CH2), 1.71-1.78 (m, 1H, CH2), 1.45-1.58 (m, 1H, CH2), 1.17-1.27 (m, 1H, CH2); 13C NMR δ 158.6, 154.5, 148.7, 143.2, 129.8, 120.5, 114.6, 76.2, 57.8, 56.5, 56.1, 53.2, 38.0, 33.1, 32.3, 29.9, 25.7, 23.2; HRMS (FAB+) calcd for C18H26N5O2 (MH+) m/z 344.2087, found 344.2090.
