A solution of 65.0 mg (0.202 mmol) of 2-[4-amino-3-(4,4-dimethyl-cyclohex-1-enyl)-phenyl]-ethanesulfonic acid methylamide (as prepared in the previous step) in CH2Cl2 (5 mL) was treated with 141 mg (0.303 mmol) of PyBroP, 67.7 mg (0.222 mmol) of 4-cyano-1-(2-trimethylsilanyl-ethoxymethyl)-1H-imidazole-2-carboxylate potassium salt (as prepared in Example 1, step (d)), and 105 μL (0.605 mmol) of DIEA at RT for 2 h. The mixture was diluted with CH2Cl2 (10 mL) and washed with saturated aqueous NaHCO3 (1×10 mL). The organic layer was dried (MgSO4) and concentrated in vacuo. Silica gel chromatography of the residue on a 50-g Varian MegaBond Elut SPE column with 50% EtOAc-hexane afforded 96.0 mg (83%) of the title compound as a white solid: Mass spectrum (ESI, m/z): Calcd. for C28H41N5O4SSi, 572.3 (M+H). found 572.0.
