Bromine → Dimethyl 3-bromothieno-[2,3-b]pyridine-5,6-dicarboxylate

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Reaction Conditions

Reaction Steps

Bromine (0.33, 0.00206 mol) in acetic acid (8 mL) is added to a stirred solution of dimethylthieno[2,3-b]pyridine-5,6-dicarboxylate (0.5 g, 0.00187 mol) in acetic acid containing sodium acetate (0.31 g, 0.00377 mol) at 40° C. The reaction mixture is heated at 75° C. for 18 hours. Evaluation of the mixture by tlc (silica gel) indicated incomplete reaction. Additional bromine (0.33 g) in acetic acid and sodium acetate (0.31 g) is added and heating at 75° C. continued for six hours. The reaction mixture is diluted with water and extracted into ethyl acetate. The separated organic layer is dried over anhydrous MgSO4, filtered, and the filtrate concentrated to an oil which solidifies on standing. Crystallization of the crude product from ethyl acetate-hexanes yields the dimethyl 3-bromothieno[2,3-b]pyridine-5,6-dicarboxylate as white needles mp 86°-87.5° C.

Provenance & Evidence