NaH (65 mg of a 60% oil dispersion, 1.62 mmol) was added to solution 5-(3,3-dimethyl-but-1-ynyl)-3-[(4-hydroxy-cyclohexyl)-(4-methyl-cyclohexanecarbonyl)-amino]-thiophene-2-carboxylic acid methyl ester (155 mg, 0.34 mmol) and (2-fluoro-pyridin-4-ylmethyl)-dimethyl-amine (130 mg, 0.84 mmol) in DMF (4.0 mL) at 0° C. After 5 min the reaction was warmed to room temperature and then heated at 65° C. for 2 h. The reaction was cooled, aqueous NaOH (0.5 mL of a 1.0 N solution) was added and the reaction mixture evaporated to dryness. Purification by column chromatography on reverse phase C18 silica gel (100% water to 20% acetonitrile/water) provided the desired product as a colorless solid (62 mg, 31%) after lyophilization. MS (m/z): 580.2 [M+H]; HPLC retention time: 5.05 min (2-98% acetonitrile:water with 0.05% trifluoroacetic acid).
