1.1: dimethyl sulfoxide / 24 h / 25 - 90 °C 1.2: 3 h / 25 - 30 °C 2.1: hydrogenchloride / tert-butyl methyl ether; acetone / 0.5 h / 25 - 30 °C 3.1: triethylamine / dichloromethane / 1 h / 12 - 22 °C 3.2: 4 h / 12 - 25 °C 4.1: 2,6-di-tert-butyl-4-methyl-phenol; sodium hydroxide; water / dimethyl sulfoxide / 0.17 h / 30 °C 4.2: 32 °C 5.1: 1,1'-carbonyldiimidazole / dichloromethane / 2 h / -10 °C / Inert atmosphere 5.2: 22 h / 0 - 30 °C 6.1: N,O-bis-(trimethylsilyl)-acetamide; 1H-imidazole; trimethylsilyl iodide / dichloromethane; isopropanol acetate / 19 h / 89 °C 6.2: 50 - 60 °C View Scheme

1.1: dimethyl sulfoxide / 24 h / 25 - 90 °C 1.2: 3 h / 25 - 30 °C 2.1: hydrogenchloride / tert-butyl methyl ether; acetone / 0.5 h / 25 - 30 °C 3.1: triethylamine / dichloromethane / 1 h / 12 - 22 °C 3.2: 4 h / 12 - 25 °C View Scheme