1.1: NaH / dimethylformamide / 1 h / 20 °C 1.2: NaI / dimethylformamide / 14 h / 80 °C 2.1: 25.1 g / NaH / dimethylformamide / 15 h / 80 °C 3.1: 21 percent / H2SO4; AcOH / 2.5 h / 90 °C 4.1: DMAP / tetrahydrofuran / 1.5 h / Heating View Scheme

1.1: 88 percent / pyridine / 1 h / 55 °C 2.1: NaH / dimethylformamide / 1 h / 20 °C 2.2: NaI / dimethylformamide / 14 h / 80 °C 3.1: 25.1 g / NaH / dimethylformamide / 15 h / 80 °C 4.1: 21 percent / H2SO4; AcOH / 2.5 h / 90 °C 5.1: DMAP / tetrahydrofuran / 1.5 h / Heating View Scheme

4-(N,N-dimethlyamino)pyridine in tetrahydrofuran 1.5 h; Heating;

1: 3.89 g / sodium methoxide / 2.5 h / Heating 2: NaBH4 / tetrahydrofuran; methanol / 1 h / -15 °C 3: Et3N / tetrahydrofuran / 14 h / 20 °C 4: 2.53 g / 1,8-diazabicyclo[5,4,0]undec-7-ene / tetrahydrofuran / 0.17 h / Heating 5: 100 percent / aq. HCl / ethyl acetate / 0.5 h / 80 °C View Scheme