Sodium Carbonate → methyl 2-(tert-butoxy)-2-[3-(3,4-dihydro-2H-1-benzopyran-6-yl)imidazo[1,2-a]pyridin-2-yl]acetate

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 2-{3-bromoimidazo[1,2-a]pyridin-2-yl}-2-(tert-butoxy)acetate (25d) (60 mg, 0.175 mmol), sodium carbonate (75 mg, 0.70 mmol), 6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)chroman (82 mg, 0.32 mmol) and palladium tetrakis(triphenylphosphine) (20 mg, 0.018 mmol) in a mixture of toluene (1.1 mL), water (0.55 mL) and ethanol (0.48 mL) was heated at 85° C. overnight. After cooling to room temperature, the mixture was poured into water (10 mL). The aqueous layer was extracted with ethyl acetate (2×5 mL). The organic layer was washed with brine (10 mL), dried over sodium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (dichloromethane/ethyl acetate 50/50). The residue containing target compound was dissolved in ethyl acetate (5 mL) and washed with 1M hydrochloric acid aqueous solution (5 mL). The acidic layer was basified with a saturated solution of sodium hydrogenocarbonate and extracted with ethyl acetate (2×5 mL). The organic layer was dried over sodium sulfate and concentrated in vacuo to provide the desired product (25e) (31 mg, 0.078 mmol, 45%).

Provenance & Evidence