2-Bromoisophthalic acid → 3-Methyl-1-(pyridin-2-yl)-1H-pyrazol-5-amine

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Reaction Steps

Following the procedure described in Reference Example 2-5, 4-[[3-methyl-1-(2-pyridinyl)-1H-pyrazol-5-yl]amino]isophthalic acid was prepared from bromoisophthalic acid and 3-methyl-1-(2-pyridinyl)-1H-pyrazol-5-ylamine (99% yield). A solution of the compound (23.0 g, 68.0 mmol) in phosphorus oxychloride (108 g, 704 mmol) was heated under reflux for I hour. The reaction solution was allowed to cool to room temperature, and the solvent was evaporated under reduced pressure. To a stirred mixture of the residue in tetrahydrofuran (100 mL), methanol (10 mL) was added dropwise carefully, and the precipitate was collected by filtration. The precipitate was dissolved in a sodium hydroxide solution, and organic matter was extracted with chloroform. The extract was washed with saturated brine and water, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (chloroform) to give the title compound (3.40 g, 14% yield).

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