To a solution of tert-butyl (3-{cyclopropyl[3-hydroxy-5-(3-methoxypropyl)benzyl](cyclopropyl)amino}-2-{4-[2-(2,6-dichloro-4-methylphenoxy)ethoxy]benzyl}-3-oxopropyl)carbamate from Example 70, Step 2 (1 eq.) in DMF (0.05 M) was added 3-(methylthio)propyl methanesulfonate from the previous step (1.4 eq.) and cesium carbonate (1.4 eq.). The resulting suspension was heated at 60° C. for 12 h. The reaction mixture was quenched sat. aq. NaHCO3 and then extracted with ether. The combined organic extracts were washed with water and brine, dried over MgSO4, filtered and the filtrate concentrated in vacuo. Purification of the crude product thus obtained by way of flash chromatography (SiO2, 3:2 (v/v) Hex:EtOAc→2:3 (v/v) Hex:EtOAc) afforded the title compound as a colorless oil.
