Pyridine → 6-amidino-1-(2-carbamoylethyl)-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]-benzoate.dihydrochloride

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Reaction Steps

45 Milliliters of 20% hydrous pyridine was added to 2.71 g of 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoic acid.hydrochloride, 3.0 g of 6-amidino-1-(2-carbamoylethyl)-2-naphthol.hydrochloride, 2.52 g of DCC and 124.6 mg of DMAP, followed by stirring for 2 hours under cooling with ice and 6 days under cooling with water. The precipitate was filtered and the filtrate was concentrated under reduced pressure. To the residue was added 15 ml of DMF, and a small amount of insoluble matter was filtered off. The filtrate was added dropwise to 400 ml of acetone, followed by stirring for 1 hour under cooling with ice and 24 hours under cooling with water. The supernatant was decanted, and to the residue was added 15 ml of methanol, followed by stirring for 1 hour under cooling with ice. The precipitate was collected by filtration to obtain a crude product. Then, the product was subjected to silica gel column chromatography using a mixed liquid of methyl ethyl ketone-water-acetic acid (80:15:5) as an eluent solvent, and the desired fractions were collected and the solvent was distilled off under reduced pressure. The residue was dissolved in 5 ml of DMF and 200 μl of concentrated hydrochloric acid, and the solution was added dropwise to 200 ml of acetone. After stirring for 1 hour under cooling with ice and then 24 hours under cooling with water, the precipitate was collected by filtration to obtain 495.4 mg of the desired product.

Provenance & Evidence