Tolvaptan → 7-chloro-1-[2-methyl-4-(2-methyl-benzoylamino)-benzoyl]-2,3,4,5-tetrahydro-1H-benzo[b]azepin-5-yl 4-dimethylaminobutyrate hydrochloride

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Reaction Steps

Tolvaptan (1.0 g, 2.2 mmol), 4-dimethylamino-butyric acid hydrochloride (0.48 g, 2.9 mmol), and 4-dimethylaminopyridine (27 mg, 0.22 mmol) were suspended in dichloromethane (5 ml). Triethylamine (0.4 ml) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (WSC) (0.55 g, 2.9 mmol) were added thereto, and the mixture was stirred at room temperature for 12 hours. An aqueous saturated sodium hydrogen carbonate solution was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated sodium chloride solution, dried over anhydrous sodium sulfate. After filtration and concentration under reduced pressure, the residue was purified by silica gel flash chromatography (n-hexane:ethyl acetate=50:50→0:100). The purified product was concentrated under reduced pressure. The residue was then dissolved in ethyl acetate, a 4N hydrogen chloride ethyl acetate solution was added thereto, and the resultant mixture was concentrated under reduced pressure. To the residue was added water (10 ml). After filtration, the filtrate was freeze-dried to obtain 0.91 g of 7-chloro-1-[2-methyl-4-(2-methyl-benzoylamino)-benzoyl]-2,3,4,5-tetrahydro-1H-benzo[b]azepin-5-yl 4-dimethylaminobutyrate hydrochloride as white amorphous solid.

Provenance & Evidence