1: 53 percent / 80percent H2SO4 / 0.5 h / 75 °C 2: 94 percent / POCl3 / dimethylformamide / 3 h / 90 °C 3: 77 percent / CAN / H2O; acetonitrile / 0.25 h / 0 °C 4: 1.) conc. HCl, 2.) K2CO3, TDA-1 / 1.) CHCl3, 35 deg C, 8 h; 5 min, RT; 2.) DMF, 25 deg C, 1 h 5: 13 percent / H2 / 10percent palladium on carbon / pyridine; methanol / 20 h View Scheme

Multi-step reaction with 2 steps 1: 53 percent / 80percent H2SO4 / 0.5 h / 75 °C2: 94 percent / POCl3 / dimethylformamide / 3 h / 90 °C  

Multi-step reaction with 3 steps 1: 53 percent / 80percent H2SO4 / 0.5 h / 75 °C2: 94 percent / POCl3 / dimethylformamide / 3 h / 90 °C3: 77 percent / CAN / H2O; acetonitrile / 0.25 h / 0 °C  

Multi-step reaction with 4 steps 1: 53 percent / 80percent H2SO4 / 0.5 h / 75 °C2: 94 percent / POCl3 / dimethylformamide / 3 h / 90 °C3: 77 percent / CAN / H2O; acetonitrile / 0.25 h / 0 °C4: 1.) conc. HCl, 2.) K2CO3, TDA-1 / 1.) CHCl3, 35 deg C, 8 h; 5 min, RT; 2.) DMF, 25 deg C, 1 h