1: 85 percent / p-TsOH / methanol; H2O / 20 h / Ambient temperature 2: 91 percent / pyridinium chlorochromate / CH2Cl2 / 2 h / Ambient temperature 3: 46 percent / piperidine, pyridine / 1) 22 deg C, 17 h, 2) 30 deg C, 6 h, then 120 deg C, 1.5 h View Scheme

1: 85 percent / p-TsOH / methanol; H2O / 20 h / Ambient temperature 2: 91 percent / pyridinium chlorochromate / CH2Cl2 / 2 h / Ambient temperature View Scheme

1: 1.) HCl / 1.) CH3OH, 2.) pyridine, room temperature, 3 h 2: 90 percent / NaBr / dimethylformamide / 40 h / 45 °C 3: 92 percent / H+ View Scheme

1: 1.) HCl / 1.) CH3OH, 2.) pyridine, room temperature, 3 h 2: 90 percent / NaBr / dimethylformamide / 40 h / 45 °C View Scheme