To a stirred solution of 2,6-dimethyl-3-[3-(methyloxy)phenyl]thieno[2,3-b]pyridin-4-amine (100 mg, 0.352 mmol) (Description 4) in THF (2 mL) cooled in an ice bath was added LiHMDS (1M solution in THF) (0.774 mL, 0.774 mmol). The reaction mixture was stirred at RT for 45 min before the addition of phenylmethanesulfonyl chloride (168 mg, 0.879 mmol). The reaction mixture was stirred at RT for a further 16 h and was then cooled in an ice bath before the addition of LiHMDS (1M solution in THF) (0.352 mL, 0.352 mmol). The reaction mixture was then stirred at RT for 1 h before the addition of phenylmethanesulfonyl chloride (67.2 mg, 0.352 mmol). The reaction mixture was stirred at RT for a further 16 h and then diluted with water (10 mL) and the aqueous layer extracted with DCM (3×20 mL). The combined organic extracts were dried over a phase separating column and concentrated. The residue was purified by MDAP (basic conditions), to afford the title compound (10 mg). LCMS (A) m/z: 439 [M+1]+, Rt 1.31 min (basic).
