pyridine 6 h;

1: 77 percent / pyridine / 24 h / Ambient temperature 2: 73 percent / 80percent acetic acid / 6 h / 65 °C 3: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 4: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C View Scheme

1: 22 percent / pyridine / 6 h 2: 75 percent / 1 N sodium methoxide / methanol / 2.5 h / 60 °C 3: 91 percent / 80percent acetic acid / 4 h / 60 °C View Scheme

1: 77 percent / pyridine / 24 h / Ambient temperature 2: 73 percent / 80percent acetic acid / 6 h / 65 °C 3: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature 4: 59 percent / t-BuOK / 2-methyl-propan-2-ol / 2.5 h / 60 °C 5: 79 percent / tetrabutyl ammonium fluoride / tetrahydrofuran / 0.33 h / Ambient temperature View Scheme

1: 77 percent / pyridine / 24 h / Ambient temperature 2: 73 percent / 80percent acetic acid / 6 h / 65 °C 3: 93 percent / imidazole / dimethylformamide / 3.5 h / Ambient temperature View Scheme