Water → 4-fluoro-benzenesulfonic acid 2-[tert-butoxycarbonyl-(3-chloro-4-methoxy-benzyl)-amino]-3H-benzoimidazol-5-yl ester

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Reaction Steps

A stirred solution of 4-fluoro-benzenesulfonic acid 2-tert-butoxycarbonylamino-3H-benzoimidazol-5-yl ester (Example 55 (step 3), 200 mg) in dry dimethylformamide (3 ml) was treated with sodium hydride (12 mg, 60% dispersion in mineral oil). After stirring for 30 minutes the mixture was treated with a solution of 3-chloro-4-methoxy-benzyl bromide (94 mg) in dimethylformamide (1 ml) and stirring was continued for a further 3 hours. The reaction mixture was poured into water (10 ml) and then extracted three times with ethyl acetate (10 ml). The combined extracts were dried over magnesium sulfate and then evaporated. The residue was subjected to flash chromatography on silica eluting with a mixture of ethyl acetate and heptane (1:2, v/v) to give 4-fluoro-benzenesulfonic acid 2-[tert-butoxycarbonyl-(3-chloro-4-methoxy-benzyl)-amino]-3H-benzoimidazol-5-yl ester (70 mg) as a beige solid.

Provenance & Evidence