The tert-butyl (3R)-3-({4-[6-(3-methoxyphenyl)imidazo[2,1-b][1,3]thiazol-5-yl]pyrimidin-2-yl}amino)piperidine-1-carboxylate (21 g, 41.5 mmol) is dissolved in 250 ml of dioxane and treated with 75 ml of anhydrous a four molar HCl in dioxane at room temperature (RT). The reaction mixture is stirred at room temperature for three hours. The mixture is then diluted with 350 ml of ether and stirred until product separates as a solid. Solid product is filtered and washed with ether. The solid is dissolved in MeOH (200 ml) and concentrated to dryness twice. The product is dried at high vacuum to yield 20.275 g of yellow solid (tris HCl salt) (90%). M.p.=220-225° C.; 300 MHz 1H NMR (DMSO-d6 at 80° C.) δ: 9.6-9.3 (br. s, 2H), 8.9-8.4 (br. s, 2H), 8.82 (s, 1H), 8.11 (d, J=5.8 Hz, 1H), 7.50 (d, J=4.7 Hz, 1H), 7.39 (t, J=7.98 Hz, 1H), 7.2-7.1 (m, 2H), 7.08-7.0 (m, 1H), 6.49 (d, J=5.8 Hz, 1H), 4.4-4.3 (m, 1H), 3.79 (s, 3H), 3.39 (d, J=10.2 Hz, 1H), 3.16 (br. s, 1H), 3.05-2.7 (m, 2H), 2.2-1.6 (m, 3H), 1.55-1.2 (m, 1H). LCMS: 407 [M+H]; calc. for C21H22N6OS 3.3 HCl 0.05 dioxane 0.3 methanol: C, 47.75; H, 5.01; N, 15.54; found. C, 47.73; H, 5.26; N, 15.55.
