A mixture of tert-butyl 4-{[(1E)-pyrimidin-4-ylmethylene]amino}piperidine-1-carboxylate (C13) (57.66 g, 198.6 mmol), 1-fluoro-4-{isocyano[(4-methylphenyl)sulfonyl]methyl}benzene (C2) (38.30 g, 132.4 mmol) and potassium carbonate (36.59 g, 264.8 mmol) in DMF (575 mL) was stirred for 18 hours. The reaction was filtered, and the solids were washed with ethyl acetate and discarded. The combined filtrates were diluted with ethyl acetate (1 L) and washed with water (2×1 L), and the combined aqueous layers were extracted with ethyl acetate (500 mL). Concentration of the combined organic layers in vacuo provided a solid, which was heated at reflux with tert-butyl methyl ether (400 mL), then cooled to room temperature and granulated for 1 hour. The solid was collected by filtration and washed with additional tert-butyl methyl ether; this filtrate was concentrated under reduced pressure and treated in the same way, using 75 mL of tert-butyl methyl ether, to obtain a second crop. The combined solids provided the product as a white solid. Yield: 41.70 g, 98.47 mmol, 74%. 1H NMR (400 MHz, CDCl3) δ 1.49 (s, 9H), 1.81-1.92 (m, 2H), 2.16 (br d, J=12 Hz, 2H), 2.77-2.85 (m, 2H), 4.30 (br s, 2H), 4.90 (tt, J=12.0, 3.8 Hz, 1H), 7.04 (dd, J=8.7, 8.7 Hz, 2H), 7.17 (dd, J=5.3, 1.4 Hz, 1H), 7.41 (dd, J=8.9, 5.4 Hz, 2H), 7.79 (s, 1H), 8.57 (d, J=5.4 Hz, 1H), 9.29 (d, J=1.5 Hz, 1H).
