1: 2.) Et3N / 1.) benzene, RT, 3 h, 2.) n-BuOH, reflux, 40 min 2: 74.4 percent / SeO2 / dioxane; H2O / 4 h / Heating 3: 92.2 percent / aq. NaOH / ethanol / 0.17 h / 40 °C 4: thionyl chloride, DMF / CH2Cl2 / 2 h 5: CH2Cl2 / 0.5 h View Scheme

1: thionyl chloride, DMF / CH2Cl2 / 2 h 2: CH2Cl2 / 0.5 h View Scheme

1: 74.4 percent / SeO2 / dioxane; H2O / 4 h / Heating 2: 92.2 percent / aq. NaOH / ethanol / 0.17 h / 40 °C 3: thionyl chloride, DMF / CH2Cl2 / 2 h 4: CH2Cl2 / 0.5 h View Scheme

1: 92.2 percent / aq. NaOH / ethanol / 0.17 h / 40 °C 2: thionyl chloride, DMF / CH2Cl2 / 2 h 3: CH2Cl2 / 0.5 h View Scheme

1: 1.) pyridine / 1.) CH2Cl2, RT, 1 h, 2.) reflux, 1 h 2: 2.) Et3N / 1.) benzene, RT, 3 h, 2.) n-BuOH, reflux, 40 min 3: 74.4 percent / SeO2 / dioxane; H2O / 4 h / Heating 4: 92.2 percent / aq. NaOH / ethanol / 0.17 h / 40 °C 5: thionyl chloride, DMF / CH2Cl2 / 2 h 6: CH2Cl2 / 0.5 h View Scheme

in dichloromethane 0.5 h; Yield given;