Sodium triacetoxyborohydride → Ethyl cis(+/-)-2-(4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-ethoxypiperidin-1-yl)-4-[(methylamino)methyl]-1,3-thiazole-5-carboxylate

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Reaction Steps

3 Å molecular sieves (500 mg) and methylamine hydrochloride (105 mg, 1.55 mmol) were added to a solution of ethyl cis(±)-2-(4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-ethoxypiperidin-1-yl)-4-formyl-1,3-thiazole-5-carboxylate obtained in Example (28a) (500 mg, 1.03 mmol) in methanol (5 mL), and the mixture was stirred at room temperature for two hours. The reaction solution was filtered, and then the filtrate was concentrated under reduced pressure. Sodium triacetoxyborohydride (437 mg, 2.06 mmol) was added to a solution of the resulting residue in dichloroethane (10 mL), and the mixture was stirred at room temperature for 20.5 hours. The reaction solution was diluted with ethyl acetate, and then the mixture was extracted with a 1 N aqueous hydrochloric acid solution. A 1 N aqueous sodium hydroxide solution was added to the aqueous layer, followed by extraction with ethyl acetate. The combined organic layers were dried over anhydrous magnesium sulfate. Following filtration, the filtrate was concentrated under reduced pressure to obtain 145 mg of the title compound as a yellow oily substance (28%).

Provenance & Evidence