Water → 5-ethoxy-6-ethyl-2-[4-nitro-1-(tetrahydropyran-2-yl)-1H-pyrazol-3-yl]-1H-benzoimidazole

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Reaction Conditions

Reaction Steps

A mixture of 4-ethoxy-5-ethyl-benzene-1,2-diamine [0.18 g, Reference Example 30(s)], 4-nitro-1-(tetrahydro-pyran-2-yl)-1H-pyrazole-3-carbaldehyde [0.225 g, Reference Example 6(m)] and sodium bisulfite (0.12 g, 1.2 mmol) in dimethylformamide (10 mL) was heated at 120° C. for 1 hour. The mixture was cooled, water (100 mL) was added and the aqueous mixture was extracted with twice ethyl acetate (50 mL). The combined extracts were evaporated and the residue was chromatographed on silica gel (ethyl acetate with gradient of 20-0% heptane) to give 5-ethoxy-6-ethyl-2-[4-nitro-1-(tetrahydropyran-2-yl)-1H-pyrazol-3-yl]-1H-benzoimidazole (200 mg) as a solid. LC-MS (Method E) RT=2.85 minutes, 386 (M+H)+.

Provenance & Evidence