A solution of CDI (117 mg, 0.722 mmol) in dry THF (5 mL) was treated with a solution of [4-(dimethylphosphoryl)phenyl]methanol (133 mg, 0.722 mmol) in DMSO (2 mL) and THF (1 mL) dropwise. The resulting solution was stirred for 1 h and then added dropwise over 5 min. to a solution of 1,1-dimethylethyl [3-({[4-(aminomethyl)phenyl]carbonyl}amino) biphenyl-4-yl]carbamate (301 mg, 0.722 mmol), Et3N (101 μL, 0.722 mmol) and DBU (109 μL, 0.722 mmol) in dry THF (5 mL). The reaction mixture was stirred at RT overnight. The reaction mixture was concentrated in vacuo, diluted with EtOAc, washed with H2O, 0.5 N HCl, dried (MgSO4), filtered and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, eluting with CHCl3/MeOH (2.5% to 20%) to give a glassy yellow solid. 1H NMR (CDCl3, 600 MHz) δ 9.28 (br s, 1H), 8.02 (s, 1H), 7.90 (d, J=8.0 Hz, 2H), 7.75-7.67 (m, 2H), 7.59 (d, J=8.0 Hz, 2H), 7.50-7.46 (m, 2H), 7.42-7.35 (m, 4H), 7.34-7.29 (m, 1H), 7.27 (d, J=8.0 Hz, 2H), 6.98 (s, 1H), 5.49 (br s, 1H), 5.18 (s, 2H), 4.41 (d, J=6.0 Hz, 2H), 1.71 (dd. J=12.9, 3.8 Hz, 6H). MS: cal'd 628 (MH+), exp 628 (MH+).
