1.1: N-ethyl-N,N-diisopropylamine / tetrahydrofuran / 2 h / 20 - 25 °C 2.1: sodium hydrogencarbonate; sodium dithionite / water; acetone / 2 h / 20 - 25 °C 3.1: sodium azide; acetic acid / toluene; water / 1 h / 5 - 10 °C 4.1: hydrogenchloride; water / toluene; methanol / 2 h / 25 - 30 °C 4.2: pH > 8 View Scheme