PPA T=175°C; 4 h;

1: 2-(2-bromophenyl)-1H-benzo[d]imidazole With sodium hydride in tetrahydrofuran; mineral oil T=20°C; 1 h; 2: dimethyl sulfate in tetrahydrofuran; mineral oil T=20°C; 3.5 h; Reflux;

sodium hydroxide in water T=20°C; 1 h; RefluxInert atmosphere;

1.1: Polyphosphoric acid / 6 h / 150 °C 2.1: sodium hydride / tetrahydrofuran; mineral oil / 1 h / 20 °C 2.2: 3.5 h / 20 °C / Reflux View Scheme

1.1: 2,6-dimethylpyridine; trifluoromethylsulfonic anhydride / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 1.2: 20 °C / |Inert atmosphere 2.1: potassium hydroxide / dimethyl sulfoxide / 16 h / 120 °C / |Inert atmosphere; |Sealed tube View Scheme

1: polyphosphoric acid / 6 h / 150 °C / |Inert atmosphere 2: sodium hydroxide / water / 1 h / 20 °C / |Reflux; |Inert atmosphere View Scheme