1: 27 percent / H2O / 5 h / 160 °C 2: 62 percent / diethyl azodicarboxylate, Ph3P / tetrahydrofuran / 18 h / Ambient temperature 3: 58 percent / piperidine / ethanol / 18 h / Heating 4: 61 percent / NaBH4, 1.0N aq. NaOH, CoCl2*6H2O, 2,2'-dipyridyl / dimethylformamide / 42 h / Ambient temperature 5: 98 percent / 2N aq. HCl / methanol / 2 h / Heating View Scheme

<b>Multi-step reaction with 4 steps<br /> </b>1: NaH / dimethylformamide; toluene / 2.5 h / 80 &deg;C<br />2: 10percent aq. H₂SO₄ / 2 h / Heating<br />3: 90 percent / NaBH₄ / ethanol / 1.5 h / 0 &deg;C<br />4: 1.) NaH / 1.) hexane, DMF, 0 deg C, 1.5 h, 2.) hexane, DMF, from -78 deg C to RT<br /> <br /> &nbsp;