1: 84 percent / Lawesson's reagent / various solvent(s) / 0.5 h / 160 °C 2: 1.) NaH / 1.) THF, reflux, 45 min, 2.) THF, reflux, 90 min View Scheme

1: 54 percent / glacial CH3COOH / various solvent(s) / 2 h / 200 °C 2: 84 percent / Lawesson's reagent / various solvent(s) / 0.5 h / 160 °C 3: 1.) NaH / 1.) THF, reflux, 45 min, 2.) THF, reflux, 90 min View Scheme

sodium hydride 1.) THF, reflux, 45 min, 2.) THF, reflux, 90 min; Yield given. Multistep reaction;