Dimethylformamide → Methyl 4-bromo-5-formylfuran-2-carboxylate

Participants

Reaction Steps

A solution of 69.65 g (0.246 mol) of methyl 4,5-dibromo-2-furoate in 700 mL of dry THF was cooled to −45° C. under argon. To this solution 141.5 mL (0.282 mol) of isopropyl magnesium chloride 2M (Aldrich) was slowly added over 45 min at −43/−48° C. and the mixture was stirred for an additional hour. The resulting suspension was treated dropwise with 56.8 mL (0.737 mol) of anhydrous DMF (Aldrich, H2O<0.005%) over 30 min at −45° C. and stirred for 15 min at the same temperature. The reaction mixture was slowly warmed to +20° C., stirred for 1 hour and then it was slowly poured in a mixture of 1.2 L of HCl 1 M and 1.0 L of MTBE. The aqueous layer was separated and extracted twice with 1.0 L and 0.5 L of MTBE. The combined organic extracts were concentrated to dryness affording 57.81 g of crude material, which was crystallized from 120 mL of hot toluene and 230 mL of n-heptane. The resulting slurry was cooled to +4° C., aged for 2 h and filtered to afford 46.55 g of beige solid.

Provenance & Evidence