sodium hydroxide in methanol 6 h; Heating;

hydrogenchloride; acetic acid in 1,4-dioxane; water T=20°C; Clauson-Kaas reaction; 24 h; Reflux;

1: dibenzopyrrole With potassium hydroxide T=260°C; 2: tetrahydrofuran-2-one T=180 - 200°C; 10 h;

1.1: NaH / dimethylformamide; tetrahydrofuran / 0.25 h / 20 °C 1.2: 32 percent / dimethylformamide; tetrahydrofuran / 10 h / 20 °C 2.1: 100 percent / aq. NaOH / methanol / 6 h / Heating View Scheme

T=200°C;