1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h 2: pyridine 3: 3.62 g / lead tetraacetate, iodine / CCl4 4: 1.5 g / Zn/HCl / dioxane 5: perchloric acid 6: 1.2 g / CrO3/pyridine / CH2Cl2 / 0.25 h / 20 °C 7: 1.) Mg,I2 / 1 h, reflux 8: 0.675 g / pyridine / 0 °C 9: 1.) sodium iodide, zinc; 2.) dilute acid / 1.) reflux, glyme 10: 1.) HBr; 2.) NaOH / 1.) 15 h, rt., AcOH; 2.) water, reflux, 6 h 11: 1.) acetic acide / 1.) 8 h, reflux 12: 0.01 g / ethyl orthoformate, benzoic acid / 70 - 170 °C View Scheme

1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h 2: pyridine 3: 3.62 g / lead tetraacetate, iodine / CCl4 4: 1.5 g / Zn/HCl / dioxane 5: perchloric acid 6: 1.2 g / CrO3/pyridine / CH2Cl2 / 0.25 h / 20 °C 7: 1.) Mg,I2 / 1 h, reflux 8: 0.675 g / pyridine / 0 °C 9: 1.) sodium iodide, zinc; 2.) dilute acid / 1.) reflux, glyme 10: 1.) HBr; 2.) NaOH / 1.) 15 h, rt., AcOH; 2.) water, reflux, 6 h View Scheme

With  sodium hydroxide in  methanol 1 h;  Heating;   

Multi-step reaction with 2 steps 1: 1.) triethylamine; 2.) 25percent HCl / 1.) chloroform, 3 h, 35 deg C; 2.) 5 h, reflux2: 85 percent / NaOH / methanol / 1 h / Heating  

With  hydrazine hydrate in  ethylene glycol  140 deg C, 1 h then 195 deg C, 6 h;   

Multi-step reaction with 2 steps 1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h2: pyridine  

Multi-step reaction with 3 steps 1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h2: pyridine3: 3.62 g / lead tetraacetate, iodine / CCl4  

Multi-step reaction with 4 steps 1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h2: pyridine3: 3.62 g / lead tetraacetate, iodine / CCl4 4: 1.5 g / Zn/HCl / dioxane  

Multi-step reaction with 5 steps 1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h2: pyridine3: 3.62 g / lead tetraacetate, iodine / CCl4 4: 1.5 g / Zn/HCl / dioxane5: perchloric acid  

Multi-step reaction with 6 steps 1: 3.5 g / hydrazine hydrate / ethane-1,2-diol / 140 deg C, 1 h then 195 deg C, 6 h2: pyridine3: 3.62 g / lead tetraacetate, iodine / CCl4 4: 1.5 g / Zn/HCl / dioxane5: perchloric acid6: 1.2 g / CrO3/pyridine / CH2Cl2 / 0.25 h / 20 °C