1: With potassium acetate; acetic anhydride in toluene 3.5 h; 2: With isopentyl nitrite in toluene T=80°C; 18 h; 3: With tetra(n-butyl)ammonium hydroxide; sodium hydroxide in methanol T=40°C; 4 h;

1: With acetic acid; zinc in methanol T=0°C; 1 h; 2: With sodium hydrogencarbonate in water; ethyl acetate

potassium carbonate in N-methyl-acetamide; water

1.1: potassium acetate; acetic anhydride / toluene / 3.5 h 1.2: 18 h / 80 °C 1.3: 4 h / 40 °C 2.1: caesium carbonate / N,N-dimethyl-formamide / 5.25 h / 40 - 90 °C 3.1: hydrogen; palladium(II) oxide hydrate / tert-butyl methyl ether / 12 h / 2430.66 Torr / |Inert atmosphere 4.1: tert-butyl methyl ether / 760.05 Torr / |Heating; |Inert atmosphere 4.2: 36 h / 65 °C / |Heating; |Inert atmosphere 5.1: potassium hydroxide / tetrahydrofuran; water / 3 h View Scheme