1: pyridine / 5 h / 70 °C 2: 1.) NaH / 1.) THF, RT, 30 min, 2.) THF, RT, overnight 3: BF3*2MeOH / CH2Cl2 / 2 h / 0 °C 4: 1.) POCl3, Et3N, 2.) pyridine / 1.) CHCl3, 60 deg C, 30 min, 2.) CHCl3, RT, overnight View Scheme

1: pyridine / 24 h / Heating 2: 82.4 percent / pyridine / benzene / 70 - 80 °C 3: BF3-MeOH / CH2Cl2 / 1 h / 0 °C 4: 56 percent / POCl3, triethylamine / hexane; toluene / Ambient temperature 5: 25 percent / pyridine / 240 h / Ambient temperature View Scheme

1: Heating 2: aq. H2O2 / acetic acid View Scheme

1: 93 percent / Et3N / acetonitrile; tetrahydrofuran 2: 94 percent / KOH / dimethylsulfoxide 3: 85 percent / aq. pTSA / methanol 4: 76 percent / MCPBA / CH2Cl2 / 20 °C View Scheme

1: pyridine / 5 h / 70 °C 2: 1.) NaH / 1.) THF, RT, 30 min, 2.) THF, RT, overnight 3: 63 percent / BF3*2MeOH / CH2Cl2 / 2 h / 0 °C View Scheme