反应详情

To a suspension of 2-methyl-1-(tetrahydropyran-4-yl)benzimidazole-5-carboxylic acid HCl salt (see Working Example 4-3) (500 mg, 1.86 mmol) in toluene (10 mL) was added thionyl chloride (3 mL), and this was stirred at reflux for 1.5 hours. This was then concentrated at reduced pressure to obtain 2-methyl-1-(tetrahydropyran-4-yl)benzimidazole-5-carboxylic acid HCl salt chloride, to a solution of which (533 mg, 1.69 mmol) in tetrahydrofuran (10 mL) was added phenylenediamine (183 mg, 1.69 mmol) and triethylamine (512 mg, 5.07 mmol), and this was stirred at room temperature for 7 hours. After the reaction was complete, 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 solution of the residue obtained in dioxane (5 mL) was added methanesulfonic acid (0.5 mL), and this was heated to reflux for 24 hours. After the reaction was complete, 1M aqueous sodium hydroxide solution was added, and this was extracted with chloroform. The organic layer obtained was dried over anhydrous sodium sulfate, filtered, and concentrated to give crude crystals that were washed with ethyl acetate to yield the title compound (300 mg, 54% yield).

1. temperatureat reflux for 1.5 hours
2. concentrationThis was then concentrated at reduced pressure