2-Thiophenecarboxaldehyde → 5-(Benzoxazol-2-yl)-2-(thiophen-2-yl)-1-(tetrahydropyran-4-yl)benzimidazole

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Reaction Steps

5-(Benzoxazol-2-yl)-2-(tetrahydropyran-4-yl)aminoaniline (see Working Example 20-2) (0.13 g, 0.42 mmol) was dissolved in DMF (3 mL) and water (0.1 mL), 2-thiophenecarbaldehyde (0.05 g, 0.45 mmol) was added followed by oxone (0.17 g, 0.28 mmol), and this was stirred at room temperature for 2.5 hours. Aqueous potassium carbonate solution (0.10 g/15 mL) was added to the reaction solution. This was extracted with ethyl acetate, washed with water, and after drying over magnesium sulfate, this was concentrated and purified by silica gel column chromatography. The crystals obtained were washed with hexane and a small amount of ethyl acetate, and dried to yield the title compound (60 mg, 36% yield) as light brown crystals.

Provenance & Evidence