1-Methylpiperazine → 4-[2-(3,5-Dichloro-4-pyridyl)-1-oxoethyl]-2-(4-methyl-1-piperazinyl)carbonyl-7-methoxybenzofuran

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Reaction Steps

4-[2-(3,5-Dichloro-4-pyridyl)-1-oxoethyl]-7-methoxybenzofuran-2-carboxylic acid (Compound M, 5.8 g) obtained in Reference Example 3 was dissolved in DMF (700 ml), and 1-hydroxybenzotriazole monohydrate (8.4 g), N-ethyl-N′-3-dimethylaminopropylcarbodiimide monohydrochloride (11.6 g) and 1-methylpiperazine (6.8 ml) were added thereto, and the mixture was stirred at room temperature for 5 hours. After the solvent was distilled off under reduced pressure, the residue was extracted with chloroform, washed with a saturated aqueous sodium chloride solution, and dried over magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified by silica gel column chromatography (chloroform:methanol 80:1 to 20:1) and then recrystallized from ethanol to give Compound 13 (5.5 g, 79%) as colorless crystals.

Provenance & Evidence