The general procedure for the synthesis of 2-hydrazinoquinoline from 2-chloroquinoline was as follows: 21.0 g (128.4 mmol) of 2-chloroquinoline was first dissolved in 210 mL of ethanol. Subsequently, 64.3 g (1.3 mol) of hydrazine hydrate was added and the reaction mixture was stirred under reflux conditions for 16 hours. Upon completion of the reaction, the mixture was cooled to 0 °C and the precipitated solid product was collected by filtration and washed with a small amount of ethanol. After initial drying, the product was further dried under high vacuum. Finally, 14.5 g of product was obtained in 71% yield. The product was analyzed by LC-MS (Method 1): retention time Rt = 1.95 min; mass spectrum (ESIpos): m/z = 160 [M + H]+; 1H-NMR (400 MHz, DMSO-d6) data were as follows: δ= 8.08 (broad peaks, 1H), 7.87 (double peaks, 1H), 7.63 (double peaks, 1H), 7.57-7.43 (multiple peaks, 2H), 7.16 (triple peaks, 1H), 6.85 (double peaks, 1H), 4.35 (broad peaks, 2H).
