Cesium carbonate → tert-butyl 2,4-dimethoxybenzyl(6-(diphenylmethyleneamino)-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

Anhydrous dioxane (4 mL) was added to a mixture of tert-butyl 6-chloro-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl(2,4-dimethoxybenzyl)carbamate (example 1B, 0.638 g, 1.474 mmol), benzophenone imine (0.297 mL, 1.769 mmol), Pd2(dba)3 (0.270 g, 0.295 mmol), 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (0.256 g, 0.442 mmol), and cesium carbonate (0.672 g, 2.063 mmol). The reaction mixture was heated to 90° C. overnight. After cooling to rt, solvent was removed in vacuo. The residue was partitioned between ethyl acetate and water. The organic layer was washed twice with water, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The crude residue was purified by flash chromatography using an Isco 40 g column eluting with 50-100% ethyl acetate/hexane to provide tert-butyl 2,4-dimethoxybenzyl(6-(diphenylmethyleneamino)-1-methyl-1H-imidazo[4,5-c]pyridin-4-yl)carbamate (0.757 g, 89% yield) as a light yellow solid.

Provenance & Evidence