3-Chlorobenzenesulphonyl chloride → Ethyl 2-bromo-4-{[(3-chlorophenyl)sulfonyl]amino}-3,6-dimethylthieno[2,3-b]pyridine-5-carboxylate

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Reaction Steps

To a stirred solution of ethyl 4-amino-2-bromo-3,6-dimethylthieno[2,3-b]pyridine-5-carboxylate (Description 31) (500 mg, 1.519 mmol) in DMF (10 mL) was added sodium tert-butoxide (365 mg, 3.80 mmol) and 3-chlorobenzenesulfonyl chloride (0.428 mL, 3.04 mmol). The whole mixture was stirred at RT under nitrogen for ca. 1.5 h. The reaction mixture was then diluted with ethyl acetate (ca. 30 mL) and water (ca. 50 mL). The organic phase was separated and the aqueous phase re-extracted with ethyl acetate (ca. 30 mL×2). The combined organic phase was dried over Na2SO4 and the solvent concentrated in vacuo. The residue was purified by normal phase chromatography, eluting with a gradient of 0-50% ethyl acetate in cyclohexane, to give the title compound (350 mg). LCMS (A) m/z: 504/506 [M+1]+, Rt 1.59 min (acidic).

Provenance & Evidence