Potassium Carbonate → tert-butyl 2-(1-(3-methoxy-4-((6-methoxypyridin-3-yl)methoxy)benzyl)-1H-benzo[d]imidazol-5-yl)-2,7-diazaspiro[3.5]nonane-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of 5-iodo-1-(3-methoxy-4-((6-methoxypyridin-3-yl)methoxy)benzyl)-1H-benzo[d]imidazole (0.61 g, 1.22 mmol) in dimethyl sulfoxide (4 mL) was added tert-butyl 2,7-diazaspiro[3.5]nonane-7-carboxylate (0.30 g, 1.34 mmol), copper(I) iodide (0.028 g, 0.15 mmol), potassium carbonate (0.41 g, 2.94 mmol), and L-proline (0.034 g, 0.29 mmol). The light yellow reaction mixture was heated to 120° C. After 16 h, the reaction mixture was allowed to cool to room temperature and was diluted with 3 N ammonium hydroxide solution (20 mL). The mixture was extracted with dichloromethane, resulting in a thick emulsion. The emulsion was filtered through Celite to remove any insoluble material. The organic phase was washed with water, brine, dried over magnesium sulfate, filtered, and concentrated. Chromatographic purification (CombiFlash, 40 g SiO2 column, 1-5% methanol/dichloromethane elute) afforded 0.53 g (72%) of tert-butyl 2-(1-(3-methoxy-4-((6-methoxypyridin-3-yl)methoxy)benzyl)-1H-benzo[d]imidazol-5-yl)-2,7-diazaspiro[3.5]nonane-7-carboxylate.

Provenance & Evidence