Phosphorus oxychloride → 2-Chloro-7-iodo-1,5-naphthyridine

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Reaction Steps

7-iodo-1,5-naphthyridin-2(1H)-one (D-16) (740 mg, 2.72 mmol, 1.0 eq) was dissolved in POCl3 (10 mL), and then heated at reflux for 1 h. The reaction was complete based on TLC analysis. The reaction mixture was concentrated in vacuo, poured into ice-water (30 mL), and neutralized with saturated sodium carbonate solution (about 30 mL) to adjust pH value to 8-9. The mixture was extracted with ethyl acetate (3×30 mL). The combined organic layer was washed with brine (50 mL), dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo. The resultant residue was purified by silica gel column chromatography (5-10% ethyl acetate/petroether) to afford the desired product, 2-chloro-7-iodo-1,5-naphthyridine (D-17) (715 mg, 90.5%) as a solid. 1H NMR (400 MHz, CDCl3-d6) δ: 9.13 (d, J=2.0 Hz, 1H), 8.74 (d, J=1.6 Hz, 1H), 8.33 (d, J=8.8 Hz, 1H), 7.66 (d, J=8.8 Hz, 1H); ESI-MS m/z: 290.93 [M+H]+.

Provenance & Evidence