1: 73 percent / NaOH / methanol / 1 h 2: 1.) DCC, Et3N, 2.) Pd-C, H2, Rh-C, Amberlite IR 45 (acetate form) / 1.) DMF, 0 deg C, 4 h, 2.) aq. AcOH, 2 h View Scheme

1: 73 percent / NaOH / methanol / 1 h 2: 70 percent / 1-hydroxybenzotriazole, DCC, Et3N / dimethylformamide / 0 deg C to room temperature 3: TFA / 0.5 h / Ambient temperature 4: 79 percent / Et3N / dimethylformamide / 16 h 5: 76 percent / Amberlite IR 45 (acetate form), H2 / Rh-C, Pd-C / aq. acetic acid / 6 h View Scheme