1: 1.) dimethyldibromohydantoin, 2.) K2CO3 / 1.) H2O, acetone, 0 deg C, 2.) MeOH 2: 84 percent / NaN3, NH4Cl / ethanol; H2O / 90 °C 3: diethylaminosulphur trifluoride (DAST) / CH2Cl2 / 0 °C 4: H2 / Lindlar catalyst / ethanol 5: benzene; dimethylformamide / 18 h / -15 - 20 °C 6: toluene-p-sulphonic acid / methanol; CH2Cl2 7: HCl / 0.5 h / Heating View Scheme

1: 84 percent / NaN3, NH4Cl / ethanol; H2O / 90 °C 2: diethylaminosulphur trifluoride (DAST) / CH2Cl2 / 0 °C 3: H2 / Lindlar catalyst / ethanol 4: benzene; dimethylformamide / 18 h / -15 - 20 °C 5: toluene-p-sulphonic acid / methanol; CH2Cl2 6: HCl / 0.5 h / Heating View Scheme

1: benzene; dimethylformamide / 18 h / -15 - 20 °C 2: toluene-p-sulphonic acid / methanol; CH2Cl2 3: HCl / 0.5 h / Heating View Scheme