1: sulfuric acid / ethanol / 16 h / 78 °C 2: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 3: sodium azide / water; ethanol / 24 h / |Reflux 4: triphenylphosphine; acetic acid / water; tetrahydrofuran / 16 h / 45 °C View Scheme

1: sulfuric acid / ethanol / 16 h / 78 °C 2: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 3: sodium azide / water; ethanol / 24 h / |Reflux 4: triphenylphosphine; acetic acid / water; tetrahydrofuran / 16 h / 45 °C 5: phosphoric acid / water; ethyl acetate; ethanol / 50 - 55 °C View Scheme

1: sulfuric acid / ethanol / 16 h / 78 °C 2: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 3: sodium azide / water; ethanol / 24 h / |Reflux 4: 5 Pd/C; hydrogen / ethanol / 3 h / 24 °C View Scheme

1: sulfuric acid / ethanol / 16 h / 78 °C 2: sodium carbonate / 0.5 h / 20 °C / pH 6.5 - 7 3: sodium azide / water; ethanol / 24 h / |Reflux View Scheme

Multi-step reaction with 4 steps 1: sodium azide; ammonium chloride / methanol / 6.5 h / 10 - 20 °C2: toluene / 1 h / 20 °C3: toluene / 7 h / |Reflux4: boron trifluoride diethyl etherate / 17 h / 0 - 20 °C  

Multi-step reaction with 3 steps 1: toluene / 1 h / 20 °C2: toluene / 7 h / |Reflux3: boron trifluoride diethyl etherate / 17 h / 0 - 20 °C