Triethylamine → (S)-3-[2-benzyloxy-4-(4-chloro-butanoylamino)-benzenesulfonylamino]-4,4-diethoxy-butyric acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-3-(4-amino-2-benzyloxy-benzenesulfonylamino)-4,4-diethoxy-butyric acid tert-butyl ester from Route J step 7 (0.958 g, 1.88 mmol), in anhydrous methylene chloride (20 mL) at 0° C. was added triethylamine (1.32 mL, 9.42 mmol) followed by 4-chlorobutyryl chloride (0.32 ml, 2.83 mmol) dropwise. The reaction was allowed to stir at 0° C. for 1 h and then allowed to slowly warm to room temperature overnight. The methylene chloride was evaporated and the reaction mixture was dissolved in ethyl acetate and water. The organic layer was collected and washed with 10% sulfuric acid, brine, dried over magnesium sulfate, and concentrated to yield (S)-3-[2-benzyloxy-4-(4-chloro-butanoylamino)-benzenesulfonylamino]-4,4-diethoxy-butyric acid tert-butyl ester (1.32 g) as a crude brown oil. MS (APCI) m/z 611.3 (M−1).

Provenance & Evidence