1,3-Dichloroisoquinoline

4456-77-3

7742-73-6

Example 60B Synthesis of 1,3-dichloroisoquinoline: The product of Example 60A, 1,3-[2H,4H]-isoquinolinedione (6.5 g, 40.4 mmol) was mixed with phenylphosphinic acid dichloride (11.5 mL, 81.1 mmol) and the reaction was heated for 3 hours at 160 °C. After the reaction was completed, it was cooled to room temperature and left to stand overnight. The reaction mixture was dissolved in tetrahydrofuran (200 mL) and hydrolyzed by adding water (60 mL), followed by concentration under reduced pressure to remove the tetrahydrofuran. The resulting aqueous phase was neutralized with concentrated NH4OH, followed by extraction with ethyl acetate. The organic phases were combined, washed sequentially with water and brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure to afford 1,3-dichloroisoquinoline as a yellow flaky solid (6.92 g, 74% yield).