1: 100 percent / thionyl chloride / 8 h / Heating 2: 78 percent / AlCl3 / 1.) 0 deg C up to RT; 2.) RT, 3 h 3: 79 percent / hydrazine hydrate / ethanol / 40 h / Heating 4: 45 percent / MnO2, KOH / diethyl ether; ethanol / 1.5 h / dark View Scheme