Methanesulfonic Acid → 5-(5-Methoxybenzoxazol-2-yl)-2-methyl-1-(tetrahydropyran-4-yl)benzimidazole

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Reaction Steps

2-methyl-1-(tetrahydropyran-4-yl)benzimidazole-5-carboxylic acid HCl salt (see Working Example 4-3) ((250 mg, 0.842 mmol), 2-amino-3-methoxyphenol (139 mg, 0.842 mmol), DMF (5 mL), and WSC (178 mg, 0.926 mmol) were stirred for 22 hours. Water was added and this was extracted with chloroform. After the organic layer obtained was dried over anhydrous sodium sulfate, it was filtered and concentrated. To a dioxane (5 mL) solution of the solid obtained was added methanesulfonic acid (283 mg, 2.95 mmol), and this was heated to reflux for 18 hours. After the reaction solution was cooled, water and saturated aqueous sodium hydrogen carbonate solution were added, and this was extracted with chloroform. After the organic layer obtained was dried over anhydrous sodium sulfate, it was filtered and concentrated. The residue obtained was purified by silica gel column chromatography to yield the title compound (10 mg, 3.3% yield) as brown crystals.

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