1: With trimethylsilyl bromide in dichloromethane T=20°C; 16 h; 2: in methanol; dichloromethane T=20°C; 2 h; Further stages.;

1: BHT; 4 M HCl / dioxane / 3 h / 50 °C 2: 73 percent / Cs2CO3 / acetonitrile / 48 h / 50 °C View Scheme