Hydrochloric Acid → 2-[2-(2-dimethylamino-ethylamino)-ethyl]-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester

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Reaction Steps

A stirred solution of 2-[(2-dimethylamino-ethylcarbamoyl)-methyl]-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester (281 mg, 1 mmol) in anhydrous tetrahydrofuran (2 ml) was added dropwise slowly with 1M borane-tetrahydrofuran complex in tetrahydrofuran (3 ml, 3 mmol) under an argon atmosphere. Upon completion of the addition, the mixture was stirred for 1 hour and heated to reflux for another 5 hours. The mixture was added with cold water (5 ml) and 1N hydrochloric acid (2 ml) and stirred for 5 minutes. The resulting solution was adjusted to pH 10 with 10% aqueous sodium hydroxide solution and extracted with ethyl acetate (10 ml×5). The combined organic extracts were washed with brine (15 ml), dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-[2-(2-dimethylamino-ethylamino)-ethyl]-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester (300 mg) as a brown oil which was used as such.

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