Pyridine → 4-Benzoyl-6-chloro-3-fluorenylmethoxycarbonylaminobenzoic acid

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Reaction Conditions

Reaction Steps

A solution was prepared by diluting 3-amino-4-benzoyl-6-chlorobenzoic acid (5.59 g, 20.3 mmol) with approximately 70 mL of CH2Cl2. Chlorotrimethylsilane (5.50 g, 51 mmol, 2.5 equivalents) was added by syringe and the resulting white slurry was heated at gentle reflux for 1.5 hours. After cooling the mixture to 0° C., pyridine (3.69 g, 46.7 mmol, 2.3 equivalents) was added by syringe, immediately followed by addition of fluorenylmethoxycarbonyl chloride (5.78 g, 22.3 mmol, 1.1 equivalents). The resulting slurry was stirred for one hour under a nitrogen atmosphere. The reaction solution was then diluted with CH2Cl2 (150 mL) and was extracted three times with 1.0N aqueous sodium bisulfate (100 mL) and once with aqueous sodium chloride (100 mL), then dried over sodium sulfate and concentrated in vacuo to give a viscous oil. Pure product was obtained in 64% yield (6.50 g) as a white solid by flash chromatography with 5 cm×25 cm silica gel and 40:60 ethyl acetate and then 75:25:1 ethyl acetate/hexane/acetic acid as the eluent. The structure was confirmed by proton NMR, carbon-13 NMR, and FAB mass spectroscopy.

Provenance & Evidence