1: 58 percent / diethyl azodicarboxylate, Ph3P / tetrahydrofuran / 18 h / Ambient temperature 2: 96 percent / 2N aq. HCl / methanol / 2 h / Heating View Scheme

1: 58 percent / diethyl azodicarboxylate, Ph3P / tetrahydrofuran / 18 h / Ambient temperature 2: 96 percent / 2N aq. HCl / methanol / 2 h / Heating 3: SOCl2 / CHCl3 / 1 h / Heating 4: dimethylformamide / 1 h / Ambient temperature 5: 65 percent / piperidine / ethanol / 18 h / Heating 6: 56 percent / NaBH4, 1.0N aq. NaOH, CoCl2*6H2O, 2,2'-dipyridyl / dimethylformamide; tetrahydrofuran / 18 h / Ambient temperature 7: 72 percent / 4N aq. HCl / 18 h / Heating View Scheme