A solution of 1-(5-(3-(4-(bis(4-methoxybenzyl)amino)-6-methyl-1,3,5-triazin-2-yl)-5-chloropyridin-2-ylamino)pyridin-2-yl)-3-(4-(2-methoxyethoxy)phenyl)urea (0.176 g, 0.231 mmol) and trifluoromethanesulfonic acid (0.020 mL, 0.231 mmol) in TFA (2 mL) was stirred at rt for 30 min then warmed up to 60° C. and stirred overnight. After cooling to rt, solid sodium carbonate was added in portions until effervescence subsided. 25% iPrOH in CHCl3 (+1% NH4OH) was added to the residue, and the organic phase was washed with sodium bicarbonate. The material was not fully soluble in the organic layer so the organic layer containing solid was directly dried under vacuum (no drying agent was added). The crude product was purified by preparative HPLC using Phenomenex, Gemni 5 micron C18 100×30 mm column (1%-90% CH3CN w/0.1% TFA/H2O w/0.1% TFA in 15 min). The fractions containing product were collected and concentrated in vacuo. Sodium bicarbonate was added and the resulting solid was collected to give 1-(5-(3-(4-amino-6-methyl-1,3,5-triazin-2-yl)-5-chloropyridin-2-ylamino)pyridin-2-yl)-3-(4-(2-methoxyethoxy)phenyl)urea (0.0834 g, 69% yield) as a yellow solid. 1H NMR (400 MHz, d6-DMSO) δ 11.82 (br. s., 1H); 10.10 (br. s., 1H); 9.30 (br. s., 1H); 8.62-8.86 (m, 2H); 8.36 (d, J=2.54 Hz, 1H); 8.13 (br. s., 7.96 (br. s., 1H); 7.84 (br. s., 1H); 7.51 (br. s., 1H); 7.33-7.46 (m, 2H); 6.90 (d, J=8.41 Hz, 2H); 4.04 (br. s., 2H); 3.64 (d, J=3.72 Hz, 2H); 3.30 (d, J=5.87 Hz, 3H); 2.44 (d, J=5.48 Hz, 3H). m/z (ESI, +ve ion) 521.9 (M+H)+.
