55687-05-3

55687-19-9

55687-05-3

Step 3: 5-chloro-2-hydroxyquinoxaline (0.60 g, 3.32 mmol) was mixed with phosphorus trichloride (10 mL, 109 mmol), heated to 90 °C and maintained for 3 hours. Upon completion of the reaction, the mixture was slowly poured into ice water and subsequently extracted with ethyl acetate. The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give a dark brown solid crude product. The crude product was purified by silica gel column chromatography using 0-30% ethyl acetate/hexane gradient elution to give 2,5-dichloroquinoxaline as a white solid (210 mg, 32% yield).