Ethyl Acetate → 5-[3-(2-dimethylamino-ethylamino)-propyl]-3-methyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester

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Reaction Steps

5-(3-Methanesulfonyloxy-propyl)-3-methyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester 1 g (11.964 g, 25.7 mmol) obtained from step 6 of Example 1 was dissolved in N,N-dimethylethylenediamine (12 ml, 97 mmol), the resulting solution was stirred for 5 hours at room temperature. After thin lay chromatography showed the disappearance of starting materials, the reaction mixture was added with ethyl acetate (80 ml) and saturated brine (80 ml), stirred for 5 minutes, and separated into layers. The organic phase was washed with saturated brine (80 ml×4) to remove N,N-dimethylethylenediamine, dried over anhydrous magnesium sulfate, filtered to remove the drying agent and concentrated under reduced pressure to obtain brown oil. The residue was purified by silica gel column chromatography to obtain the title compound 5-[3-(2-dimethylamino-ethylamino)-propyl]-3-methyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester 23a (5.85 g, yield 45.9%) as a yellow oil.

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