110-91-8

141-30-0

17259-32-4

GENERAL METHOD: Anhydrous ethanol (5 mL) and 3,6-dichloropyridazine (3.36 mmol) were added to a 50 mL round-bottomed flask, followed by triethylamine (5.03 mmol) and morpholine (5.03 mmol). The reaction mixture was refluxed in ethanol (for 3,6-dichloropyridazine and 2,6-dichloropyrazine) or stirred at room temperature (for 2,4-dichloropyrimidine). The reaction process is monitored by gas chromatography (GC). After the starting material 3,6-dichloropyridazine was completely consumed, the reaction mixture was poured into saturated ammonium chloride solution (20 mL) and extracted with dichloromethane (3 x 20 mL). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was ground with petroleum ether and filtered through a Büchner funnel to give the pure 4-(6-chloropyridazin-3-yl)morpholine.