2,2'-Bipyridine → 1-(5-bromo-3-methylpyridin-2-yl)-10-chloro-7-(1-ethylpropyl)-2,3,4,5-tetrahydro-1H-[1,3]diazepino[1,2-a]benzimidazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 10-chloro-7-(1-ethylpropyl)-2,3,4,5-tetrahydro-1H-[1,3]diazepino[1,2-a]benzimidazole (Reference example 72, 1.0 g, 3.42 mmol), 2,5-dibromo-3-methylpyridine (1.72 g, 6.85 mmol), copper(I) iodide (650 mg, 3.42 mmol), 2,2′-bipyridyl (1.07 g, 6.85 mmol) and cesium carbonate (2.23 g, 6.85 mmol) in 1-methyl-2-pyrrolidinone (10 mL) was stirred at 150° C. for 12 hr. The mixture was diluted with ethyl acetate, filtered through a pad of celite, washed with water and brine, dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by flash chromatography on silica gel eluting with a 5-30% ethyl acetate/n-hexane gradient mixture. The filtrate was concentrated in vacuo to give 1-(5-bromo-3-methylpyridin-2-yl)-10-chloro-7-(1-ethylpropyl)-2,3,4,5-tetrahydro-1H-[1,3]diazepino[1,2-a]benzimidazole (870 mg, 55%) as a colorless solid and 1-(6-bromo-5-methylpyridin-3-yl)-10-chloro-7-(1-ethylpropyl)-2,3,4,5-tetrahydro-1H-[1,3]diazepino[1,2-a]benzimidazole (130 mg, 8%) as a colorless solid.

Provenance & Evidence