Reaction Steps
2-(2,6-Dimethyl-1-piperidinyl)ethylamine (280) (0.66 g, 4.3 mmol) was added to a stirred solution of chloride 21 (314 mg, 1.4 mmol) in DME (50 mL) and the solution stirred at reflux temperature for 3 h. The solvent was evaporated and the residue partitioned between DCM (100 mL) and dilute aqueous NH3 solution (50 mL). The organic fraction was dried and the solvent evaporated. The residue was purified by chromatography, eluting with a gradient (0-10%) of MeOH/DCM, to give 1-oxide 38 (389 mg, 80%) as a yellow solid: mp (MeOH) 173-175° C.; 1H NMR δ 8.07 (s, 1H, H-9), 7.38 (s, 1H, H-5), 5.47 (br s, 1H, NH), 3.50-3.55 (m, 2H, CH2N), 2.96-3.03 (m, 4H, CH2N, CH2), 2.87-2.91 (m, 2H, CH2), 2.48-2.57 (m, 2H, CH2N), 2.10-2.18 (m, 2H, CH2), 1.64-1.69 (m, 1H, CH2), 1.53-1.58 (m, 2H, CH2), 1.33-1.38 (m, 1H, CH2), 1.24-1.31 (m, 2H, CH2), 1.20 (d, J=6.3 Hz, 6H, 2×CH3); 13C NMR δ 158.8, 154.5, 148.8, 143.2, 129.8, 120.6, 114.7, 57.2 (2), 47.5, 39.4, 34.3, 33.1 (2), 32.3, 25.8, 24.4, 21.7 (2). Anal. calcd for C19H27N5O: C, 66.8; H, 8.0; N, 20.5. Found: C, 66.8; H, 7.8; N, 20.6%.
