1: 68 percent / pivalic acid / 5 h / 150 °C 2: 77 percent / EtONa / ethanol / 15 h / Ambient temperature 3: 1.) NaH / 1) THF, rt, 1 h; 2) THF, rt, 12 h 4: 92 percent / Pd(PPh3)4, Na2CO3 / tetrahydrofuran; H2O / 1) rt, 1 h; 2) reflux, 1 h 5: 1.) p-toluenesulfonhydrazide, p-TsOH*H2O, 2.) NaBH3CN / 1) EtOH, reflux, 7 h; 2) EtOH, reflux, 4 h 6: 77 percent / aq. NaOH / ethanol / 0.25 h / 80 °C View Scheme

1: 1.) NaH / 1) THF, rt, 1 h; 2) THF, rt, 12 h 2: 92 percent / Pd(PPh3)4, Na2CO3 / tetrahydrofuran; H2O / 1) rt, 1 h; 2) reflux, 1 h 3: 1.) p-toluenesulfonhydrazide, p-TsOH*H2O, 2.) NaBH3CN / 1) EtOH, reflux, 7 h; 2) EtOH, reflux, 4 h 4: 77 percent / aq. NaOH / ethanol / 0.25 h / 80 °C View Scheme

1: 1.) p-toluenesulfonhydrazide, p-TsOH*H2O, 2.) NaBH3CN / 1) EtOH, reflux, 7 h; 2) EtOH, reflux, 4 h 2: 77 percent / aq. NaOH / ethanol / 0.25 h / 80 °C View Scheme

1: 92 percent / Pd(PPh3)4, Na2CO3 / tetrahydrofuran; H2O / 1) rt, 1 h; 2) reflux, 1 h 2: 1.) p-toluenesulfonhydrazide, p-TsOH*H2O, 2.) NaBH3CN / 1) EtOH, reflux, 7 h; 2) EtOH, reflux, 4 h 3: 77 percent / aq. NaOH / ethanol / 0.25 h / 80 °C View Scheme

1: 90 percent / n-Bu4NI, NaI, NaOH / H2O; toluene / 50 °C 2: 80 percent / NaBH(OAc)3, Et3N / CH2Cl2 / Ambient temperature 3: 68 percent / t-BuCO2H / 150 °C 4: 77 percent / EtONa / ethanol / Ambient temperature 5: 80 percent / NaH / tetrahydrofuran / Ambient temperature 6: 92 percent / Pd(PPh3)4, Na2CO3 / H2O; tetrahydrofuran / Heating 7: 1.) p-toluenesulfonyl hydrazide, p-TsOH, 2.) NaBH3CN / 1.) EtOH, reflux, 2.) EtOH, reflux 8: 77 percent / NaOH / ethanol; H2O / 80 °C View Scheme

1.1: diethyl ether / 2 h / Reflux 1.2: 3 h / Reflux 2.1: sodium hydrogencarbonate / ethanol / 36 h / 20 °C 3.1: tetrahydrofuran / 10 - 15 °C 3.2: 0.33 h / 25 - 30 °C 4.1: hydrazine hydrate; potassium hydroxide / ethylene diglycol / 7 h / 85 - 145 °C View Scheme

1.1: dimethyl sulfoxide / 36 h / 100 °C 2.1: pyridine; thionyl chloride / 0 °C 3.1: diethyl ether / 2 h / Reflux 3.2: 3 h / Reflux 4.1: sodium hydrogencarbonate / ethanol / 36 h / 20 °C 5.1: tetrahydrofuran / 10 - 15 °C 5.2: 0.33 h / 25 - 30 °C 6.1: hydrazine hydrate; potassium hydroxide / ethylene diglycol / 7 h / 85 - 145 °C View Scheme

1.1: pyridine; thionyl chloride / 0 °C 2.1: diethyl ether / 2 h / Reflux 2.2: 3 h / Reflux 3.1: sodium hydrogencarbonate / ethanol / 36 h / 20 °C 4.1: tetrahydrofuran / 10 - 15 °C 4.2: 0.33 h / 25 - 30 °C 5.1: hydrazine hydrate; potassium hydroxide / ethylene diglycol / 7 h / 85 - 145 °C View Scheme

1.1: thionyl chloride / dichloromethane / 5 - 10 °C 2.1: dimethyl sulfoxide / 36 h / 100 °C 3.1: pyridine; thionyl chloride / 0 °C 4.1: diethyl ether / 2 h / Reflux 4.2: 3 h / Reflux 5.1: sodium hydrogencarbonate / ethanol / 36 h / 20 °C 6.1: tetrahydrofuran / 10 - 15 °C 6.2: 0.33 h / 25 - 30 °C 7.1: hydrazine hydrate; potassium hydroxide / ethylene diglycol / 7 h / 85 - 145 °C View Scheme

1: water / tetrahydrofuran / 0.33 h / 25 - 30 °C 2: hydrazine hydrate; potassium hydroxide / diethylene glycol / 7 h / 85 - 145 °C View Scheme