1: HBr / acetic acid / 1 h / 20 °C 2: 74 percent / 4 Angstroem molecular sieves / AgOTf / CH2Cl2 / 36 h / 20 °C 3: Et3N; MeSiCl3 / tetrahydrofuran / 24 h / 60 °C 4: 44 mg / H2O / tetrahydrofuran / 0.5 h 5: pyridine / 2 h / 20 °C View Scheme

1: HBr / acetic acid / 1 h / 20 °C 2: 75 percent / 4 Angstroem molecular sieves / AgOTf / CH2Cl2 / 36 h / 20 °C 3: Et3N; MeSiCl3 / tetrahydrofuran / 24 h / 60 °C 4: 31 mg / H2O / tetrahydrofuran / 0.5 h 5: 100 percent / pyridine / 2 h / 20 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1.1: NaHCO₃ / CHCl₃; H₂O / 1 h / 25 &deg;C<br />1.2: 92 percent / pyridine / 12 h / 25 &deg;C<br />2.1: NH₂NH₂*HOAc / dimethylformamide / 4 h / 25 &deg;C<br />2.2: 61 percent / DBU / CH₂Cl₂ / 12 h / 25 &deg;C<br /> <br /> &nbsp;