Pyridine → 3-Benzyloxy-4-(1-tert-butoxycarbonylmethyl-2,2-diethoxy-ethylsulfamoyl)-benzoic acid methyl ester

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Reaction Steps

To a solution of (S)-3-amino-4,4-diethoxy-butyric acid tert-butyl ester (3.38 g, 13.7 mmol) in anhydrous methylene chloride (130 mL) was added pyridine (3.3 mL, 41 mmol) followed by 3-benzyloxy-4-chlorosulfonyl-benzoic acid methyl ester (4.66 g, 13.7 mmol). The reaction was allowed to stir at room temperature overnight. Mass spectrometry and TLC analysis showed presence of starting material. An additional 2 equivalents of pyridine (2.2 mL, 27.3 mmol) was added and allowed to stir overnight. TLC analysis showed the reaction to be completed. The methylene chloride was evaporated and the reaction mixture was dissolved in ether and 5% aqueous citric acid. The organic layer was collected and washed with 5% citric acid and then brine, dried over magnesium sulfate, filtered, and concentrated to yield 3-benzyloxy-4-(1-tert-butoxycarbonylmethyl-2,2-diethoxy-ethylsulfamoyl)-benzoic acid methyl ester (6.82 g, 12.4 mmol, 90%) as an orange tar. MS (APCI) m/z 550.3 (M−1).

Provenance & Evidence