A mixture of 4-(bicyclo[1.1.1]pentan-1-ylamino)-2-chloropyrimidine-5-carboxamide (44 g), (1S,3R)-3-aminocyclohexanol (27.6 g), potassium carbonate (38.2 g) and DMSO (300 mL) was heated at 85° C. for 12 h. After cooling to room temperature, water (2 L) and a mixture of THF and EtOAc (1:1, 2 L) were added. The aqueous phase was separated and the organic layer was washed with saturated brine (2 L). The organic layer was concentrated under reduced pressure to give the crude product as a purple foam which was triturated with hot acetonitrile (1 L). After cooling to room temperature the solid was filtered and washed with acetonitrile (200 mL). The solids was dried in a vacuum oven at 50° C. to give 4-(bicyclo[1.1.1]pentan-1-ylamino)-2-(((1R,3S)-3-hydroxycyclohexyl)amino)pyrimidine-5-carboxamide as an off-white solid (4 g, 79% yield). 1H NMR (DMSO-d6) δ 0.91-1.31 (m, 4H), 1.60-1.89 (m, 3H), 2.01-2.20 (m, 7H), 3.34 (s, 1H), 3.37-3.52 (m, 1H), 3.58-3.85 (m, 1H), 4.65 (d, J=4.3 Hz, 1H), 6.90 (br. s., 1H), 7.20 (d, J=7.9 Hz, 1H), 7.61 (br. s., 1H), 8.37 (s, 1H), [9.23 (s, 0.14H)], 9.41 (s, 0.86H).
