A solution of 6-(adamantan-1-ylmethoxy)-5-cyclopropylnicotinic acid (0.43 g, 1.31 mmol) and carbonyldiimidazole (0.42 g, 2.62 mmol) in anhydrous tetrahydrofuran (22 mL) was refluxed under nitrogen for 30 min. The reaction mixture was cooled to ambient temperature and treated with 1,8-Diazabicyclo[5.4.0]undec-7-ene (0.59 mL, 3.93 mmol) and methylsulfonamide (0.54 g, 3.93 mmol). The resulting mixture was stirred at ambient temperature for 2 h. The reaction mixture was diluted with ethyl acetate (60 mL), washed with 1 M aqueous hydrochloric acid (2×30 mL) and brine (50 mL); dried over anhydrous sodium sulfate; filtered and concentrated in vacuo. The residue was purified by flash chromatography eluting with 30% ethyl acetate (containing 0.2% acetic acid) in hexanes to afford the title compound as a white solid (0.31 g, 58%); 1H NMR (300 MHz, DMSO-d6) δ 12.01 (br s, 1H), 8.47 (d, J=2.5 Hz, 1H), 7.72 (d, J=2.5 Hz, 1H), 3.93 (s, 2H), 3.33 (s, 3H), 2.07-1.98 (m, 1H), 1.97-1.90 (m, 3H), 1.72-1.56 (m, 12 H), 0.98-0.90 (m, 2H), 0.76-0.70 (m, 2H); MS (ES+) m/z: 405.2 (M+H).
