1: With sodium methylate in methanol T=20°C; 0.5 h; 2: With sulfuric acid in methanol T=-60°C; 2 h;

1.1: NaH / tetrahydrofuran / 0.67 h / 20 °C 1.2: tetrahydrofuran / 24 h / 20 °C 2.1: NaOMe / methanol / 0.5 h / 20 °C 2.2: H2SO4 / methanol / 2 h / -60 °C View Scheme

1.1: NaH / tetrahydrofuran / 0.67 h / 20 °C 1.2: tetrahydrofuran / 24 h / 20 °C 2.1: NaOMe / methanol / 0.5 h / 20 °C 2.2: H2SO4 / methanol / 2 h / -60 °C View Scheme

1.1: piperidine / methanol / 0.5 h / Heating 1.2: 73 percent / methanol / 70 h / Heating 2.1: NaH / tetrahydrofuran / 0.67 h / 20 °C 2.2: 98 percent / tetrahydrofuran / 24 h / 20 °C 3.1: MeONa / methanol / 0.5 h / 20 °C 3.2: 92 percent / H2SO4 / methanol / 2 h / -60 °C View Scheme

1: NaBH4; aq. NaOH / methanol / 20 h / 20 °C 2: aq. K2CO3 / 0.25 h / 0 - 4 °C View Scheme