Hydrochloric Acid → 2,2-Difluoro-5-iodo-6-methoxybenzo[d][1,3]dioxole

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Reaction Conditions

Reaction Steps

2,2-Difluoro-6-methoxybenzo[d][1,3]dioxol-5-amine (1.4 g, 6.9 mmol) was dissolved in dichloromethane (5 mL) and added in portions to rapidly stirred concentrated HCl (75 mL) to form a loose white slurry. The mixture was cooled to 0-5° C. and treated in portions with sodium nitrite (710 mg, 10 mmol) in water (10 mL). After 40 min, this mixture was poured as a thin stream into a solution of sodium iodide (3.1 g, 21 mmol) in water (75 mL) rapidly stirred with dichloromethane (50 mL). After 45 min, the mixture was stirred with 15% NaHSO3 solution (20 mL) for 10 min. The separated aqueous phase was extracted with dichloromethane (30 mL), and the combined extracts were washed with saturated NaCl (15 mL), dried (Na2SO4) and evaporated. The material was purified by chromatography on silica with a 0-15% ethyl acetate-hexane gradient to afford the title compound as a white solid (1.8 g, 83%): mp 50-51° C.; 1H NMR (400 MHz, CDCl3) δ 7.45 (s, 1H), 6.69 (s, 1H), 3.86 (s, 3H); 19F NMR (376 MHz, CDCl3) δ −49.81 (s); EIMS m/z 314.

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