1: 86.2 percent / triethylamine / CH2Cl2 / 0.5 h / cooling 2: 1) 57percent NaH / 1) 1h, DME; 2) DME, 16h, reflux 3: KOH / methanol; H2O / 18 h / Heating 4: various solvent(s) / Heating 5: 2N HCl / acetone / 5 h / Heating 6: 80.6 percent / p-toluenesulfonic acid / 5 h / Heating View Scheme

1: 86.2 percent / triethylamine / CH2Cl2 / 0.5 h / cooling 2: 1) 57percent NaH / 1) 1h, DME; 2) DME, 16h, reflux 3: KOH / methanol; H2O / 18 h / Heating 4: various solvent(s) / Heating 5: 2N HCl / acetone / 5 h / Heating 6: 87 percent / p-toluenesulfonic acid / 17 h / Heating View Scheme

1: 86.2 percent / triethylamine / CH2Cl2 / 0.5 h / cooling 2: 1) 57percent NaH / 1) 1h, DME; 2) DME, 16h, reflux 3: KOH / methanol; H2O / 18 h / Heating 4: various solvent(s) / Heating 5: 2N HCl / acetone / 5 h / Heating 6: 87 percent / p-toluenesulfonic acid / 17 h / Heating 7: 95.8 percent / pyridine; ethanol / 22 h / Ambient temperature 8: 84.6 percent / 25percent (i-Bu)2AlH / benzene; hexane / 1.5 h / 0 - 5 °C 9: 77.9 percent / triethylamine / CH2Cl2 / 0.5 h 10: 57percent NaH / 1,2-dimethoxy-ethane / 18 h / Heating 11: 64.2 percent / KOH / H2O; methanol / 18 h / Heating 12: 84 percent / various solvent(s) / Heating 13: 90 percent / 2N HCl / acetone / 5 h / Heating 14: 94.9 percent / p-toluenesulfonic acid / 17 h / Heating View Scheme

1: 86.2 percent / triethylamine / CH2Cl2 / 0.5 h / cooling 2: 90.6 g / dimethylformamide / 3 h / 70 °C 3: NaOH / methanol; H2O / 72 h / Heating 4: 63.3 percent / 2N HCl / acetone / 5 h / Heating 5: 87.3 percent / p-toluenesulfonic acid / 17 h / Heating View Scheme

1: 86.2 percent / triethylamine / CH2Cl2 / 0.5 h / cooling 2: 1) 57percent NaH / 1) 1h, DME; 2) DME, 16h, reflux 3: KOH / methanol; H2O / 18 h / Heating 4: various solvent(s) / Heating 5: 2N HCl / acetone / 5 h / Heating View Scheme