1: 62 percent / Ph3P; diisopropyl azodicarboxylate / dioxane / 24 h / 20 °C 2: 82 percent / MeOH / 15 h / Heating 3: 89 percent / DBU / dimethylformamide / 4 h / 20 °C View Scheme

1: 62 percent / Ph3P; diisopropyl azodicarboxylate / dioxane / 24 h / 20 °C 2: 56 percent / aq. NH3 / methanol / 24 h / 20 °C View Scheme

1: 62 percent / Ph3P; diisopropyl azodicarboxylate / dioxane / 24 h / 20 °C 2: 82 percent / MeOH / 15 h / Heating 3: 89 percent / DBU / dimethylformamide / 4 h / 20 °C 4: 89 percent / dimethylformamide / 24 h / 20 °C 5: 80 percent / Ph3P; diisopropyl azodicarboxylate / dioxane / 24 h / 20 °C 6: 52 percent / conc. aq. NH3 / methanol / 24 h / 20 °C View Scheme