Potassium Carbonate → 3-[5-(5-chloro-thiophen-2-yl)-isoxazol-3-ylmethyl]-2-(1-cyclopropyl-piperidin-4-ylcarbamoyl)-3H-benzoimidazole-5-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

17.3 g (50.52 mmol) 2-(1-Cyclopropyl-piperidin-4-ylcarbamoyl)-1H-benzoimidazole-5-carboxylic acid methyl ester were dissolved in 800 mL DMF. Subsequently 10.47 g (75.8 mmol) K2CO3 and 14.84 g (50.52 mmol) methanesulfonic acid 5-(5-chloro-thiophen-2-yl)-isoxazol-3-ylmethyl ester were added and the resulting mixture was stirred for 2 h at 80° C. The mixture was concentrated under reduced pressure. The residue was suspended in 800 mL ethyl acetate. The next day the resulting precipitate was filtered off and washed with 100 mL ethyl acetate to give 3-[5-(5-chloro-thiophen-2-yl)-isoxazol-3-ylmethyl]-2-(1-cyclopropyl-piperidin-4-ylcarbamoyl)-3H-benzoimidazole-5-carboxylic acid methyl ester. The filtrate was concentrated to a volume of approx. 100 mL. Again the formed precipitate was filtered off. That procedure was repeated once again. The remaining filtrate was concentrated under reduced pressure and finally purified by flash-chromatography on silica gel using ethyl acetate as eluent. The product containing fractions were concentrated under vacuo to give pure (>98%) 1-[5-(5-Chloro-thiophen-2-yl)-isoxazol-3-ylmethyl]-2-(1-cyclopropyl-piperidin-4-ylcarbamoyl)-1H-benzoimidazole-5-carboxylic acid methyl ester as a light brown crystalline solid.

Provenance & Evidence