Citric Acid → 3-benzyloxy-4-[(S)-2-tert-butoxycarbonyl-1-(methoxy-methyl-carbamoyl)-ethylsulfamoyl]-benzoic acid

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Reaction Steps

To a solution of 3-benzyloxy-4-[(S)-2-tert-butoxycarbonyl-1-(methoxy-methyl-carbamoyl)-ethylsulfamoyl]-benzoic acid methyl ester (8.20 g, 15.3 mmol) in tetrahydrofuran (150 mL) at room temperature was added 1N lithium hydroxide (30.5 mL, 15.3 mmol). The reaction was stirred at room temperature for 3.5 h. The reaction was then diluted with ethyl acetate (300 mL) and acidified to pH 2 with 5% citric acid. The organic layer was then washed with saturated sodium chloride, dried over magnesium sulfate, filtered and concentrated under reduced pressure to yield 3-benzyloxy-4-[(S)-2-tert-butoxycarbonyl-1-(methoxy-methyl-carbamoyl)-ethylsulfamoyl]-benzoic acid as a white foam (2.9 g, 100%). MS(ACI) m/z 521.1 (M−H).

Provenance & Evidence