1: POCl3, pyridine 2: SOCl2 View Scheme

thionyl chloride

1.1: sodium nitrite; sulfuric acid / water / 1 h / 12 - 16 °C / Reflux 1.2: 20 °C 2.1: trichlorophosphate / pyridine / 2 h / Reflux View Scheme

1.1: sodium hydroxide; water / methanol / 0.83 h / 20 °C / |Inert atmosphere 2.1: sulfuric acid / water / 20 - 50 °C 2.2: 1.58 h / 10 - 100 °C / |Reflux 3.1: pyridine; trichlorophosphate / 2 h / |Reflux 3.2: 3 h / |Reflux View Scheme