Sodium Carbonate → 4-({[(9H-fluoren-9-yl)methoxy]carbonyl}amino)-2-nitrobenzoic acid

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Reaction Steps

To a solution of 11.4 g 4-amino-2-nitro-benzoic acid in 228 ml of water containing 6.63 g of sodium carbonate were added 17.0 g of 9-fluorenylmethyl-chloroformate and dropwise 20 ml of dioxane. After stirring for 20 hours under nitrogen, the mixture was filtered and the filtrate was washed five times with methyl-tert.-butylether. Residual methyl-tert.-butylether was removed from the aqueous phase by evaporation under vacuum. To the aqueous phase were added 456 g of 0° C. cold water. The mixture was adjusted to pH=3 by addition of 31 ml of 2M aqueous hydrochloric acid. The precipitate was sucked off, washed with 513 ml of water, dried at 40° C. in vacuum to give 17.0 g of 4-(((9H-fluorene-9-yl)methoxy)carbonylamino)-2-nitrobenzoic acid as off-white crystals.

Provenance & Evidence