1.1: pyridine; hydrazine hydrate; acetic acid / 75 - 80 °C / Inert atmosphere 2.1: pyridine / dichloromethane / 0 - 20 °C / Inert atmosphere 3.1: H2NC(=NH)NH2*carbonate / dichloromethane; ethyl acetate / 60 °C 3.2: 80 °C 4.1: sodium methylate; methanol / 30 - 40 °C View Scheme