1: With potassium acetate in chloroform T=20°C; 12 h; 2: With tert.-butylnitrite; 18-crown-6 ether in chloroform T=65°C; 3 h;

1.1: sodium carbonate / N,N-dimethyl-formamide / 8 h / 60 °C 2.1: ammonium chloride; iron / ethanol; water / 1 h / 90 °C 3.1: potassium acetate / chloroform / 12 h / 20 °C 3.2: 3 h / 65 °C View Scheme

1.1: ammonium chloride; iron / ethanol; water / 1 h / 90 °C 2.1: potassium acetate / chloroform / 12 h / 20 °C 2.2: 3 h / 65 °C View Scheme

1.1: 1,3-dibromo-5,5-dimethyl-hydantoin; sulfuric acid / 5 h / 20 °C 2.1: sodium carbonate / N,N-dimethyl-formamide / 8 h / 60 °C 3.1: ammonium chloride; iron / ethanol; water / 1 h / 90 °C 4.1: potassium acetate / chloroform / 12 h / 20 °C 4.2: 3 h / 65 °C View Scheme

1: With hydrogenchloride in methanol; water T=60°C; 8 h; 2: With sodium hydrogencarbonate in methanol; water pH=8;