Water → 5-(Di-tert-butoxycarbonylamino-methyl)-2-nitro-benzoic acid methyl ester

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Reaction Conditions

Reaction Steps

A stirred mixture of 5-bromomethyl-2-nitro-benzoic acid methyl ester (50.5 g, 184 mmol), di-tert-butyl iminodicarboxylate (40.15 g, 185 mmol), cesium carbonate (123.1 g, 377.7 mmol), and lithium iodide (1.23 g, 9.21 mmol) in 2-butanone (556 mL) was heated to reflux in a 100° C. oil bath for 12 hours while stirred with a mechanical stirrer. The mixture was allowed to cool to room temperature. To the mixture, was added brine (300 mL), water (300 mL), and ethyl acetate (750 mL), and the mixture was stirred for 10 minutes. The suspension was filtered through a pad of Celite. The two layers were separated, and the organic layer was evaporated to a less volume. The aqueous layer was extracted with ethyl acetate (2×150 mL). The combined organic layers were washed with brine (500 mL), dried over magnesium sulfate while de-colored at the same time by charcoal at room temp with stirring for 30 minutes. The black mixture was filtered through a pad of Celite. The filtrate was evaporated to give 5-(di-tert-butoxycarbonylamino-methyl)-2-nitro-benzoic acid methyl ester as a brown oil (74.18 g, 98% yield). The product was used in the next step without further purification.

Provenance & Evidence