1: aq. AcOH, conc. HCl / 3 h / Ambient temperature 2: 100 percent / KOH / methanol / 3 h / Ambient temperature 3: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h View Scheme

1: aq. AcOH, conc. HCl / 3 h / Ambient temperature 2: 100 percent / KOH / methanol / 3 h / Ambient temperature 3: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 4: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature View Scheme

1: aq. AcOH, conc. HCl / 3 h / Ambient temperature 2: 100 percent / KOH / methanol / 3 h / Ambient temperature 3: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 4: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature 5: 48 percent / 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 64 h / Ambient temperature 6: H2 / 10percent Pd/C / ethanol / 16 h 7: 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 16 h / Ambient temperature View Scheme

1: aq. AcOH, conc. HCl / 3 h / Ambient temperature 2: 100 percent / KOH / methanol / 3 h / Ambient temperature 3: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 4: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature 5: 48 percent / 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 64 h / Ambient temperature View Scheme