Reaction Steps
Morpholine (0.64 mL, 7.3 mmol) was added to a solution of aldehyde 101 (0.47 g, 1.8 mmol) in EtOH (20 mL) at 0° C. and the solution stirred for 30 min. NaCNBH3 (0.35 g, 5.5 mmol) was added and the mixture stirred at 0° C. for 30 min, then HOAc (0.5 mL) was added and the mixture stirred at 20° C. for 30 min. The solvent was evaporated and the residue partitioned between DCM and water, the organic phase was dried, the solvent evaporated and the residue purified by chromatography, eluting with a gradient (0-10%) of MeOH/EtOAc, to give (i) starting material 101 (83 mg, 17%) and (ii) alcohol 103 (134 mg, 28%) as a white solid: mp (MeOH/EtOAc) 70-71° C.; 1H NMR δ 8.21 (s, 1H, H-9), 7.71 (s, 1H, H-5), 3.78 (t, J=6.1 Hz, 2H, CH2O), 3.20-3.28 (m, 2H, CH2), 3.15 (t, J=7.2 Hz, 2H, CH2), 2.64-2.78 (m, 3H, H-7, CH2), 2.35 (br s, 1H, OH), 2.12-2.19 (m, 2H, CH2), 1.19 (d, J=6.4 Hz, 3H, CH3); 13C NMR δ 165.7, 154.6, 148.7, 147.3, 132.3, 122.6, 114.4, 62.1, 41.2, 40.9, 35.0, 30.6, 24.7, 20.2. Anal. calcd for C14H17N3O2.¼H2O: C, 63.7; H, 6.7; N, 15.9. Found: C, 63.7; H, 6.6; N, 15.9%; and (iii) 1-oxide 102 (331 mg, 55%) as a yellow gum: 1H NMR δ 8.22 (s, 1H, H-9), 7.70 (s, 1H, H-5), 3.60 (br t, J=4.7 Hz, 4H, 2×CH2O), 3.21-3.28 (m, 2H, CH2), 3.05 (br t, J=7.4 Hz, 2H, CH2), 2.65-2.77 (m, 3H, H-7, CH2), 2.47-2.54 (m, 6H, 3×CH2N), 2.11 (p, J=7.3 Hz, 2H, CH2), 1.19 (d, J=6.4 Hz, 3H, CH3); 13C NMR δ 165.7, 154.4, 148.5, 147.5, 132.3, 122.7, 114.4, 66.7 (2), 55.1, 53.5 (2), 41.2, 40.9, 35.2, 35.0, 24.7, 20.2; MS (FAB+) m/z 392 (MH+, 100%), 311 (20); HRMS (FAB+) calcd for C18H25N4O2 (MH+) m/z 329.1978, found 329.1978.
