1: 80 percent / TsOH*H2O / 1.) r.t., 24 h, 2.) 50 deg C, 7 h 2: 100 percent / 1 M aq. NaOH / ethanol / 18 h / Ambient temperature 3: (COCl)2, DMF / toluene / 1 h 4: CBrCl3, 2-mercaptopyridine N-oxide sodium salt, 4-(dimethylamino)pyridine / 1 h / 80 °C / Irradiation 5: aq. AcOH, conc. HCl / 3 h / Ambient temperature 6: 100 percent / KOH / methanol / 3 h / Ambient temperature 7: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h View Scheme

1: 80 percent / TsOH*H2O / 1.) r.t., 24 h, 2.) 50 deg C, 7 h 2: 100 percent / 1 M aq. NaOH / ethanol / 18 h / Ambient temperature 3: (COCl)2, DMF / toluene / 1 h 4: CBrCl3, 2-mercaptopyridine N-oxide sodium salt, 4-(dimethylamino)pyridine / 1 h / 80 °C / Irradiation 5: aq. AcOH, conc. HCl / 3 h / Ambient temperature 6: 100 percent / KOH / methanol / 3 h / Ambient temperature 7: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 8: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature View Scheme

1: 80 percent / TsOH*H2O / 1.) r.t., 24 h, 2.) 50 deg C, 7 h 2: 100 percent / 1 M aq. NaOH / ethanol / 18 h / Ambient temperature 3: (COCl)2, DMF / toluene / 1 h 4: CBrCl3, 2-mercaptopyridine N-oxide sodium salt, 4-(dimethylamino)pyridine / 1 h / 80 °C / Irradiation 5: aq. AcOH, conc. HCl / 3 h / Ambient temperature 6: 100 percent / KOH / methanol / 3 h / Ambient temperature 7: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 8: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature 9: 48 percent / 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 64 h / Ambient temperature 10: H2 / 10percent Pd/C / ethanol / 16 h 11: 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 16 h / Ambient temperature View Scheme

1: 80 percent / TsOH*H2O / 1.) r.t., 24 h, 2.) 50 deg C, 7 h 2: 100 percent / 1 M aq. NaOH / ethanol / 18 h / Ambient temperature 3: (COCl)2, DMF / toluene / 1 h 4: CBrCl3, 2-mercaptopyridine N-oxide sodium salt, 4-(dimethylamino)pyridine / 1 h / 80 °C / Irradiation 5: aq. AcOH, conc. HCl / 3 h / Ambient temperature 6: 100 percent / KOH / methanol / 3 h / Ambient temperature 7: 84 percent / propan-2-ol / 1.) 70 deg C, 9 h, 2.) r.t., 16 h 8: 86 percent / trifluoroacetic acid / 1 h / Ambient temperature 9: 48 percent / 1-hydroxybenzotriazole hydrate, dicyclohexylcarbodiimide, N-ethylmorpholine / tetrahydrofuran / 64 h / Ambient temperature View Scheme

1: 2 N NaOH / dioxane; H2O / 0.5 h 2: 9.3 mg / HCl / dioxane / 0.5 h / Ambient temperature View Scheme