Ammonium Chloride → 8-Amino-4-(4-chloro-5-methoxy-2-methylanilino)[1]benzothieno[3,2-b]pyridine-3-carbonitrile

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Reaction Steps

A mixture of 476 mg (1.12 mmol) of 4-(4-chloro-5-methoxy-2-methylphenylamino)-8-nitrobenzo[4,5]thieno[3,2-b]pyridine-3-carbonitrile, 180 mg (3.22 mmol) of iron powder and 180 mg (3.36 mmol) of ammonium chloride in 20 mL of 50% aqueous methanol is heated at reflux temperature for 2 hours. An additional 80 mg (1.42 mmol) of iron powder and 100 mg (1.87 mmol) of ammonium chloride are added and the reaction mixture is heated at reflux temperature for 2 hours, then stirred at room temperature overnight. The reaction mixture is heated at reflux for 4 hours then cooled slightly and filtered. The solid residue is extracted with several portions of hot ethyl acetate followed by hot methanol. All the organic layers are combined and washed with water. The organic layer is dried over magnesium sulfate, filtered and concentrated in vacuo. The residue is purified by flash chromatography eluting with a gradient of 1:1 hexane/ethyl acetate to only ethyl acetate to give 165 mg (37%) of a tan solid, mp 266-268° C. dec.

Provenance & Evidence