Potassium Hydroxide → tert-Butyl 4-(3-amino-4-(aminomethyl)phenyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of compound 19 (1.5 g, 3.85 mmol) in ethanol (20 mL) at room temperature was added a solution of KOH (3M, 25 mL), and the reaction was refluxed for 12 h. The reaction was cooled to room temperature, ice cold water was added, and the solution was extracted with ethyl acetate (30 mL×2). The organic layer was washed with brine (15 mL), dried over Na2SO4 and evaporated to get a brown oil material, which was resolved over silica column, eluting with ethyl acetate:hexanes (8:2), and then changing to ethyl acetate (100%) to obtain 0.98 g (83%) of 20 as a dark brown gum. IR (KBr) νmax. cm−1: 3060 (Ar-H), 1690 (C═O), 1616, 1514, 1417 (C═C). 1H NMR (500 MHz, CDCl3) δ=1.46 (s, 9H, (CH3)3C); 2.90 (m, 4H, 2CH2); 3.49 (m, 4H, 2CH2), 3.90 (s, 2H, CH2); 5.30 (br. s, 4H, 2NH2); 6.59 (d, 1H, J=8.2 Hz, H-5); 6.68 (dd, 1H, J=2.6, 8.2 Hz, H-6); 6.80 (d, 1H, J=2.6, H-2); 13C NMR (125.7 MHz, CDCl3) δ=28.37 (CH3)3C), 42.10 (CH2), 44.01 (CH2), 50.87 (CH2), 79.64 (CH3)3C), 117.29 (C-2), 117.79 (C-6), 119.88 (C-4), 120.36 (C-5), 139.80 (C-3), 144.15 (C-1), 154.67 (C═O). Calculated (%) for C16H26N4O2(306.21); C, 62.72; H, 8.55; N, 18.29. found (%) C, 62.63; H, 8.63; N, 18.20.

Provenance & Evidence