ammonium acetate in N,N-dimethyl-formamide 2 h; Heating;

1: 77 percent / ammonium acetate / toluene / 5 h / Heating 2: 56 percent / dimethylformamide / 1) RT, 3.5 h, 2) reflux, 24 h 3: 88 percent / Brederck's reagent / dioxane / 2.5 h / Heating 4: 90 percent / ammonium acetate / dimethylformamide / 2 h / Heating View Scheme

1: 56 percent / dimethylformamide / 1) RT, 3.5 h, 2) reflux, 24 h 2: 88 percent / Brederck's reagent / dioxane / 2.5 h / Heating 3: 90 percent / ammonium acetate / dimethylformamide / 2 h / Heating View Scheme

1: 88 percent / Brederck's reagent / dioxane / 2.5 h / Heating 2: 90 percent / ammonium acetate / dimethylformamide / 2 h / Heating View Scheme