1: 62 percent / pyridine / 2 h / Heating 2: 81 percent / phosphorus oxychloride / 2 h / 60 °C 3: 95 percent / sodium / Ambient temperature 4: 77 percent / NaOH / methanol; H2O / 1 h / 65 °C 5: 1.) triethylamine, ethylchloroformate / 1.) DMF, 0 deg C, 30 min, 2.) room temp. View Scheme

1: 77 percent / NaOH / methanol; H2O / 1 h / 65 °C 2: 1.) triethylamine, ethylchloroformate / 1.) DMF, 0 deg C, 30 min, 2.) room temp. View Scheme

1: 81 percent / phosphorus oxychloride / 2 h / 60 °C 2: 95 percent / sodium / Ambient temperature 3: 77 percent / NaOH / methanol; H2O / 1 h / 65 °C 4: 1.) triethylamine, ethylchloroformate / 1.) DMF, 0 deg C, 30 min, 2.) room temp. View Scheme

1: 95 percent / sodium / Ambient temperature 2: 77 percent / NaOH / methanol; H2O / 1 h / 65 °C 3: 1.) triethylamine, ethylchloroformate / 1.) DMF, 0 deg C, 30 min, 2.) room temp. View Scheme

chloroformic acid ethyl ester; triethylamine 1.) DMF, 0 deg C, 30 min, 2.) room temp.; Yield given. Multistep reaction;