1: 90 percent / NaOAc, hydrogen / Pd/C / methanol / Rt, 1 h; 35 deg C, 2 h 2: 97 percent / Dowex 50W400 / 4 h / Ambient temperature 3: 1) BH3*Me2S, 2) EtOH / 1) THF, 14 h, RT, 2) 2 h, reflux 4: 1) HCl, 2) Dowex 1X8-200 / 1) reflux, 30 min View Scheme