1: 54 percent / p-toluenesulfonic acid / cyclohexane / Heating 2: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 3: aq. NaOH / 2 h / 60 °C 4: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 5: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature 6: KHSO4 / 180 °C View Scheme

1: 43 percent / aq. HCl, NaCl, CuC / toluene / 6 h / 50 °C 2: 54 percent / p-toluenesulfonic acid / cyclohexane / Heating 3: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 4: aq. NaOH / 2 h / 60 °C 5: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 6: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature 7: KHSO4 / 180 °C View Scheme

1: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 2: aq. NaOH / 2 h / 60 °C 3: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 4: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature 5: KHSO4 / 180 °C View Scheme

potassium hydrogensulfate T=180°C; Title compound not separated from byproducts;

pyridine; selenium(IV) oxide in ethanol 1.5 h; Heating; Title compound not separated from byproducts;

selenium(IV) oxide; ethanol

selenium(IV) oxide Title compound not separated from byproducts;

T=93 - 95°C;