187973-60-0

61070-99-3

General method: Copper iodide (CuI, 0.1 mmol), L-hydroxyproline (0.2 mmol), 6-iodopyridazin-3-amine (1.3 mmol), and potassium phosphate (K3PO4, 3.0 mmol) were sequentially added to a 10 mL round-bottomed flask fitted with a magnetic stirrer under nitrogen protection. After displacing the air in the flask with nitrogen, anhydrous dimethyl sulfoxide (DMSO, 1.5 mL) solution with the corresponding amine (1.0 mmol) dissolved was injected. The reaction mixture was stirred at 50 °C for 24 hours. Upon completion of the reaction, methanol (MeOH, 5 mL) and water (H2O, 5 mL) were added and the reaction solution was neutralized by dropwise addition of acetic acid (AcOH). After the solids were precipitated, the supernatant was transferred to a strong cation exchange (SCX) column. The residual solid was washed with additional methanol (5 mL), and the wash solution was similarly loaded onto the column. After slowly eluting the column, the column was rinsed with methanol and the methanol wash solution was discarded. The column was then eluted with ammonia-containing methanol solution until the target product was completely eluted. The product-containing eluate was collected and concentrated under reduced pressure to remove the solvent to obtain the crude product. Finally, the crude product was purified by fast column chromatography on silica gel with an elution gradient from 0% to 10% volume fraction of methanol (MeOH) in dichloromethane (CH2Cl2). The fraction containing the target product was collected and evaporated to dryness under reduced pressure to give pure 3,6-diaminopyridazine.