Sodium Carbonate → 4-({[(9H-Fluoren-9-yl)methoxy]carbonyl}amino)-1-methyl-1H-pyrrole-2-carboxylic acid

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Reaction Steps

After dissolving 9 (10.9 g, 57.2 mmol) into distilled water (80 ml), sodium hydroxide (9.2 g) was added to the solution. After stirring overnight, the solution was neutralized with 1N hydrochloric acid, followed by distillation under a reduced pressure. The residue was dissolved into a mixed solution of water and ethyleneglycoldimethylether (100 ml, 1:1, v/v) to be used for next reaction. After dissolving sodium carbonate (5.3 g) into the solution, 9-fluorenylmethylchloroformate (17.8 g, 68.6 mmol) was added thereto. After stirring the mixture overnight, precipitates were collected by filtration to obtain 11 (12.3 g, 34.1 mmol). The filtrate was added to a mixed solution of 1M sodium carbonate solution and diethylether (1:1, v/v). Precipitates were collected by filtration to further obtain 11 (3.4 g). After acidifying the water layer with 10% hydrochloric acid, the water layer was extracted with ethyl acetate. The organic layer was distilled under a reduced pressure and then recrystallized with hexane-dioxane to further obtain 11 (1.6 g). (Total yield: 17.3 g, 84%)

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