Sodium Dithionite → HCID 59727080, compound

Participants

Reaction Steps

A solution of (R)-tert-butyl 5-(5-cyano-2-nitrophenylamino)-2-oxo-3-(1-(pyridin-3-yl)ethyl)-2,3-dihydroimidazo[4,5-b]pyridine-1-carboxylate (70) (100 mg) in THF (5 mL) was treated with an aqueous solution comprised of 0.5 g of Na2S2O4 and 0.25 g NaHCO3 in 5 mL of water. The mixture went quickly from a red color to a slightly yellow color, which indicated reduction of the nitro group. The mixture was diluted with ethyl acetate and washed with saturated sodium chloride solution. The organic layer was separated, dried over sodium sulfate, filtered, and concentrated to provide the intermediate (R)-tert-butyl 5-(2-amino-5-cyanophenylamino)-2-oxo-3-(1-(pyridin-3-yl)ethyl)-2,3-dihydroimidazo[4,5-b]pyridine-1-carboxylate (71). The intermediate was dissolved in THF (5 mL), DMF (1 mL), and trimethylorthoformate (2 mL). The mixture was treated with 10 mg of p-toluenesulfonic acid and stirred for 20 h. The mixture was diluted with ethyl acetate and washed once with saturated sodium bicarbonate and twice with saturated NaCl solution. The organic layer was separated, dried over sodium sulfate, filtered, and concentrated. Column chromatography (2% MeOH in methylene chloride) provided 57 mg tert-Butyl 5-(6-cyano-1H-benzo[d]imidazol-1-yl)-2-oxo-3-((R)-1-(pyridin-3-yl)ethyl)-2,3-dihydroimidazo[4,5-b]pyridine-1-carboxylate (72).

Provenance & Evidence