Sodium Dithionite → HCID 59726998, compound

Participants

Reaction Steps

5-(1H-Benzo[d]imidazol-1-yl)-3-(pyridin-3-ylmethyl)-1H-imidazo[4,5-b]pyridin-2(3H)-one (50) and 5-(1H-benzo[d]imidazol-1-yl)-3-(pyridin-3-ylmethyl)-3H-imidazo[4,5-b]pyridine (51). A solution of 6-(1H-benzo[d]imidazol-1-yl)-3-nitro-N-(pyridin-3-ylmethyl)pyridin-2-amine (48) (50 mg) in 1 mL of DMSO was treated with a solution of Na2S2O4 (300 mg) in 1 mL of water. The mixture was stirred for two hours and diluted with 50 mL of ethyl acetate. The mixture was washed three times with 50 mL aliquots of saturated sodium chloride solution, dried over sodium sulfate, filtered, and concentrated in vacuo to provide the intermediate 6-(1H-benzo[d]imidazol-1-yl)-N2-(pyridin-3-ylmethyl)pyridine-2,3-diamine (49). Half of the intermediate was dissolved in methylene chloride (2 mL) and treated with 1,1′-carbonyldiimidazole (46 mg) at RT for 16 h. The resulting crude mixture was purified by preparative TLC (1000 microns, 5% MeOH/CH2Cl2) to provide 7.1 mg of 5-(1H-benzo[d]imidazol-1-yl)-3-(pyridin-3-ylmethyl)-1H-imidazo[4,5-b]pyridin-2(3H)-one (50): 1H-NMR (CDCl3) δ 10.0 (br s, 1H), 8.9 (s, 1H), 8.6 (d, 1H), 8.5 (s, 1H), 7.9 (m, 2H), 7.8 (m, 1H), 7.6 (d, 1H), 7.4 (m, 2H), 7.4 (m, 1H), 7.3 (d, 1H), 5.2 (s, 2H). The other half of the reduced intermediate was dissolved in 1 mL of formic acid and heated in a microwave at 220° C. for 10 minutes. The mixture was concentrated in vacuo, diluted with methylene chloride, and washed with saturated aqueous sodium bicarbonate solution. The organic layer was separated, dried with sodium sulfate, filtered, and concentrated in vacuo.

Provenance & Evidence