1: 74 percent / triethylamine / benzene; dioxane / 4 h / 0 °C 2: 1.) 90percent trifluoroacetic acid; 2.) sulphuric acid / 1.) ethanol, chloroform, 10 min, room t.; 2.) 4 h, room t. View Scheme

1: 91 percent 2: 74 percent / triethylamine / benzene; dioxane / 4 h / 0 °C 3: 1.) 90percent trifluoroacetic acid; 2.) sulphuric acid / 1.) ethanol, chloroform, 10 min, room t.; 2.) 4 h, room t. View Scheme

sulfuric acid; trifluoroacetic acid 1.) ethanol, chloroform, 10 min, room t.; 2.) 4 h, room t.; Yield given. Multistep reaction;

hydrogen bromide; acetic anhydride in chloroform; water; acetic acid Ambient temperature; Yield given;