Bromine → Ethyl 4-amino-2-bromo-6-methylthieno[2,3-b]pyridine-5-carboxylate

Participants

Reaction Steps

To a stirred solution of ethyl 4-amino-6-methylthieno[2,3-b]pyridine-5-carboxylate (Description 65) (1 g, 4.23 mmol) in acetic acid (3 mL) was added bromine (0.65 mL, 12.70 mmol) and the resulting mixture stirred at RT overnight (ca. 18 h). The reaction was quenched by pouring the reaction mixture into water and the aqueous solution was basified with NaOH (5M) and diluted with ethyl acetate (30 mL). The organic layer was separated and the aqueous layer was re-extracted with ethyl acetate (20 mL×3). The combined organics were washed with saturated sodium thiosulphate solution, dried and concentrated. Purification by chromatography on silica, eluting with a gradient of 0-30% ethyl acetate in DCM afforded the title compound (1.16 g). LCMS (A) m/z: 315/317 [M+1]+, Rt 0.95 min (acidic).

Provenance & Evidence