1.1: 9.40 g / 4-(dimethylamino)pyridine / acetonitrile / 1.5 h / 20 °C 2.1: sodium bis(trimethylsilyl)amide; N,N'-dimethylpropyleneurea / tetrahydrofuran / 0.5 h / -78 °C 2.2: tetrahydrofuran / 2 h 3.1: 6.48 g / hydrogen peroxide / tetrahydrofuran / 2 h / 20 °C 4.1: hydrogen / palladium on carbon / methanol 4.2: 77 percent / hydrochloric acid / Heating View Scheme