selenium(IV) oxide in 1,4-dioxane T=90°C; 4 h;

1: nitric acid; sulfuric acid / 2.5 h / 0 - 115 °C 2: trifluoroacetic anhydride / dichloromethane / 72 h / 20 °C 3: ethanol / 24 h / |Reflux 4: selenium(IV) oxide / 1,4-dioxane / 4 h / 90 °C View Scheme

1: trifluoroacetic anhydride / dichloromethane / 72 h / 20 °C 2: ethanol / 24 h / |Reflux 3: selenium(IV) oxide / 1,4-dioxane / 4 h / 90 °C View Scheme

1: ethanol / 24 h / |Reflux 2: selenium(IV) oxide / 1,4-dioxane / 4 h / 90 °C View Scheme