1.1: pyridine / 10 h / 45 - 50 °C 2.1: NaH / tetrahydrofuran / 1 h / 20 °C 2.2: tetrahydrofuran / 4 h / 50 °C 3.1: p-TsOH; MeOH / CH2Cl2 / 8 h / 20 °C 4.1: pyridine / diethyl ether; tetrahydrofuran / 4 h / Heating 4.2: H2O; pyridine / diethyl ether; tetrahydrofuran / 1 h 5.1: CHCl3; propan-2-ol; various solvent(s) / 5 h / 65 °C View Scheme

1.1: pyridine / 10 h / 45 - 50 °C 2.1: NaH / tetrahydrofuran / 1 h / 20 °C 2.2: tetrahydrofuran / 4 h / 50 °C 3.1: p-TsOH; MeOH / CH2Cl2 / 8 h / 20 °C View Scheme

1: pyridine 2: NaH 3: TsOH / methanol; CH2Cl2 View Scheme

1.1: pyridine 2.1: NaH 3.1: TsOH / methanol; CH2Cl2 4.2: water / dimethylformamide; CHCl3; propan-2-ol View Scheme