1.1: 4-(N,N-dimethlyamino)pyridine / tetrahydrofuran / 3 h / 20 - 35 °C 2.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / tetrahydrofuran / 24 h / 35 - 50 °C 3.1: hydrogen / palladium(II) oxide hydrate / ethanol / 5 h / 30 °C / 155.15 Torr 4.1: sodium hydroxide; water / ethanol / 16 h 4.2: 1 h / 0 - 5 °C / pH 1 View Scheme