Reaction Steps
A 20 mL vial was charged with 5d (763 mg, 1.79 mmol), and NMP (10 mL). The vial was capped with a septum and placed in an oil bath heated to 120° C. DBU (267 μL, 1.79 mmol) was added, and the mixture was stirred for 2 min. Then iodopropane (175 μL, 1.79 mmol) was added and the mixture was stirred for 20 min. A second dose of DBU (267 μL, 1.79 mmol), followed by iodopropane (175 μL, 1.79 mmol), was added, and 20 min later, a third identical round of DBU and iodopropane was again added. After the third round of reagents was added and the mixture was stirred for 20 min, the reaction mixture was removed from heat and added to ethyl acetate. The solution was washed three times with water, then washed with brine, dried over Na2SO4, filtered, and concentrated to dryness. The residue was chromatographed (silica, CHCl3), yielding a colorless solid (506 mg, 61%): mp 242-243° C.; 1H NMR (d6-acetone) δ 0.89 (t, J=7.2 Hz, 3H), 1.17-1.19 (m, 21H), 1.86-1.96 (m, 2H), 4.53 (t, J=7.6 Hz, 2H), 7.75 (d, J=8.0 Hz, 2H), 7.91 (d, J=8.0 Hz, 2H), 8.36 (s, 1H), 8.50 (s, 1H); 13C NMR (d6-acetone) δ 10.5, 11.3, 18.4, 23.2, 47.1, 93.1, 106.6, 108.1, 108.3, 116.8, 116.9, 118.3, 125.8, 126.3, 129.6, 129.9, 132.5, 138.5, 145.4, 158.4; Anal. Calcd for C29H34N4Si: C, 74.63; H, 7.34; N, 12.01. Found: C, 74.75; H, 7.32; N, 12.01.
