1.1: sodium dithionite; sodium carbonate / methanol; water / 16 h / 40 °C 2.1: isopentyl nitrite / acetonitrile / 2 h / 70 °C 3.1: sodium hydride / tetrahydrofuran / 1 h / -20 °C 3.2: 16 h / -20 °C 4.1: lithium borohydride / tetrahydrofuran / 16 h / 0 °C 5.1: phosphoric acid / ethanol / 24 h / 20 °C View Scheme