Ammonium Chloride → 2-tert-Butoxycarbonylamino-3-fluorobenzoic acid 2-hydroxyethyl ester

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Reaction Steps

To a solution of 2-tert-butoxycarbonylamino-3-fluorobenzoic acid 2-(tert-butyldimethylsilanyloxy)ethyl ester from Example 19B (1.2 g, 2.9 mmol) in THF (25 ml) was added a solution tetrabutylammonium fluoride (1.0M, 5.8 ml, 5.8 mmol) in THF while cooling in an ice/water bath. The mixture was allowed to warm to room temperature and stirred for 18 h. Saturated ammonium chloride solution (20 ml) was added and the mixture was stirred for 1 h and evaporated in vacuo. The residue was partitioned between chloroform and water and the organic phase was dried and evaporated in vacuo. The residue was purified by flash chromatography on silica (eluant EtOAc:pet.ether 90:10) to give a colourless gum; yield 180 mg, 21%.

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