Water → 5-(2-Hydroxy-4-nitroanilinocarbonyl)-2-methyl-1-(tetrahydropyran-4-yl)benzimidazole

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Reaction Steps

To a suspension of 2-methyl-1-(tetrahydropyran-4-yl)benzimidazole-5-carboxylic acid HCl salt (see Working Example 4-3) (0.75 g, 2.9 mmol) in toluene (10 mL) containing DMF (1 drop) was added thionyl chloride (0.41 g, 3.4 mmol), and this was refluxed for 7 hours with stirring. After the reaction was complete, concentration at reduced pressure gave a residue that was added to 2-hydroxy-5-nitroaniline (0.44 g, 2.9 mmol), triethylamine (0.32 g, 3.2 mmol) and tetrahydrofuran (5 mL), and this was stirred at room temperature for 3 hours. After the reaction was complete, water (30 mL) was added and the precipitated crystals were filtered off. After the crystals were washed with water, they were dried with heating at reduced pressure to yield the title compound (195 mg, 17.1%) as a light brown solid.

Provenance & Evidence