phosphorus tribromide 1.) 25 deg C, 12 h, 2.) 80 deg C, 1 h;

1: phosphorous tribromide / 1.) 25 deg C, 12 h, 2.) 80 deg C, 1 h 2: NaI / dimethylformamide / 3 h / 50 °C 3: 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / dimethylformamide / 3 h / 80 °C View Scheme

1: phosphorous tribromide / 1.) 25 deg C, 12 h, 2.) 80 deg C, 1 h 2: NaI / dimethylformamide / 3 h / 50 °C 3: 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / dimethylformamide / 3 h / 80 °C View Scheme