Lithium Hydroxide → (Z)-2-[8-(2-ethyl-4,6-dimethylbenzimidazol-1-yl)methyl-6,11-dihydrodibenzo[b,e]oxepin-11-ylidene]propiononitrile

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Reaction Steps

[step 1] (Z)-2-(8-Hydroxymethyl-6,11-dihydrodibenzo[b,e]oxepin-11-ylidene)propiononitrile (150 mg, 0.54 mmol) was dissolved in THF (5.5 mL), and the solution was added with 2,6-lutidine (0.378 mL, 3.25 mmol), lithium bromide (282 mg, 3.25 mmol) and methanesulfonic anhydride (236 mg, 1.35 mmol), followed by stirring at room temperature for 16 hr. Ethyl acetate was added to the mixture, and the organic layer was washed with brine. The organic layer was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give a residue. The obtained residue and 2-ethyl-4,6-dimethylbenzimidazole (123 mg, 0.71 mmol) were dissolved in DMF (3.0 mL) and the solution was added with lithium hydroxide (24 mg, 0.98 mmol) at 0° C., followed by stirring at room temperature for 2 hr. Ethyl acetate was added to the mixture, and the organic layer was washed with brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=7/3-6/4) to give (Z)-2-[8-(2-ethyl-4,6-dimethylbenzimidazol-1-yl)methyl-6,11-dihydrodibenzo[b,e]oxepin-11-ylidene]propiononitrile (219 mg, 93%).

Provenance & Evidence