Hydrochloric Acid → Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

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Reaction Steps

Potassium (E)-2-chloro-3-ethoxy-3-oxoprop-1-en-1-olate (4.4 g, 23 mmol; prepared as in Example 65, step B1) was suspended in toluene (40 mL) and a 4M solution of HCl in dioxane (2.0 mL, 8.1 mmol). The mixture was stirred at ambient temperature for 5 minutes. 4-Bromopyridin-2-amine (2.0 g, 12 mmol) was added to the mixture and heated to 40° C. for 22 hours. The mixture was cooled to ambient temperature and extracted with 2M HCl (3×75 mL). Solid K2CO3 was added to the combined aqueous extracts until CO2 evolution ceased. The aqueous phase was extracted with MTBE (2×50 mL), dried over MgSO4, filtered and concentrated to give the product (2.4 g). MS (ES+APCI) m/z=268.7 (M+H).

Provenance & Evidence