1.1: N-bromosuccinmide / tetrahydrofuran; water / 0 - 10 °C / Large scale reaction 2.1: sodium hydrogencarbonate / acetonitrile / 3 h / Reflux; Large scale reaction 3.1: hydrogenchloride / 1,4-dioxane / 2 h / 25 °C / Large scale reaction 4.1: N-ethyl-N,N-diisopropylamine / dichloromethane / Large scale reaction 4.2: 0 °C / Large scale reaction 5.1: hydrazine hydrate / ethanol; tert-butyl methyl ether / 16 h / 40 °C 5.2: 40 °C 6.1: 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine / dichloromethane / 12 h / 20 °C View Scheme

1.1: N-bromosuccinmide / tetrahydrofuran; water / 0 - 10 °C / Large scale reaction 2.1: sodium hydrogencarbonate / acetonitrile / 3 h / Reflux; Large scale reaction 3.1: hydrogenchloride / 1,4-dioxane / 2 h / 25 °C / Large scale reaction 4.1: N-ethyl-N,N-diisopropylamine / dichloromethane / Large scale reaction 4.2: 0 °C / Large scale reaction 5.1: hydrazine hydrate / ethanol; tert-butyl methyl ether / 16 h / 40 °C 5.2: 40 °C View Scheme