1: K2CO3 / tetrahydrofuran; methanol / 30 h / 25 °C 2: SOCl2 / CHCl3 / 5 h / 25 °C 3: DBN / benzene / 4 h / 80 °C View Scheme

With  potassium carbonate in  tetrahydrofuran; methanol T=25°C; 30 h;