Phenol → (S)-3-{4-Amino-2-[(R)-1-methyl-2-(2-methylsulfanyl-benzoimidazol-1-yl)-ethoxy]-benzenesulfonylamino-}4,4-diethoxy-butyric Acid Tert-Butyl Ester

Participants

Reaction Steps

To a 0° C. solution of (S)-3-(4-amino-2-hydroxy-benzenesulfonylamino)-4,4-diethoxy-butyric acid tert-butyl ester (200 mg, 0.48 mmol), (2S)-1-[2-(methylsulfanyl)-1H-benzo[d]imidazol-1-yl]propan-2-ol (150 mg, 0.67 mmol) and resin bound triphenyl phosphine (1 g, 1 mmol) in THF (5 mL) was added diisopropyl azodicarboxylate (600 uL, 3 mmol). This mixture was shaken at room temperature for 2 h. TLC 50% ethyl acetate/heptane shows no phenol rf 0.2. The reaction mixture was filtered, the resin was washed with dichloromethane, the organics were combined, the solvent was evaporated under reduced pressure. (S)-3-{4-amino-2-[(R)-1-methyl-2-(2-methylsulfanyl-benzoimidazol-1-yl)-ethoxy]-benzenesulfonylamino}-4,4-diethoxy-butyric acid tert-butyl ester was purified by silica gel chromatography ethyl acetate/heptane (132 mg, 44%). RP-HPLC (10 to 9O % acetonitrile in 0.1 N aqueous ammonium acetate over 10 min at 2 mL/min using a Waters Symmetry C18 150×4.6 mm column) 9.8 min.

Provenance & Evidence