Hydrochloric Acid → 2-[(3-Chloropropyl)amino]-4-methoxy-3-nitrobenzoic acid

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Reaction Steps

A mixture of 6-methoxy-7-nitro-1H-indole-2,3-dione (1.44 g, 6.37 mmol), cesium carbonate (6.22 g, 19.09 mmol) and 1-chloro-3-iodopropane (2.05 mL, 19.09 mmol) in N,N-dimethylacetamide (30 mL) was stirred at room temperature for 3 hr. 1N Aqueous sodium hydroxide (30 mL) was added to the reaction mixture at 0° C. and the mixture was stirred at room temperature for 0.5 hr. To the reaction mixture was added 30% aqueous hydrogen peroxide (1.08 mL) at 0° C. and the mixture was stirred at 50° C. for 0.5 hr. The mixture was acidified with 6N hydrogen chloride at 0° C. and the mixture was extracted with ethyl acetate. The organic layer was washed with aqueous sodium thiosulfate, water (×3) and brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel eluting with a 0-20% methanol/ethyl acetate gradient mixture to give the title compound (1.776 g, 6.15 mmol, 97%) as a yellow solid.

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