To a 5 mL round bottom flask were added commercially available 4-(3-amino-1H-indazol-5-yl)-6-(2-isobutoxyphenyl)pyrimidin-2(1H)-one (100 mg, 0.26 mmol), formaldehyde (0.12 g of 37% H2O solution, 1.6 mmol), dimethylformamide (2 mL) and glacial acetic acid (1 drop). The reaction mixture was stirred at room temperature for 1 h, after which time sodium cyanoborohydride (1M THF solution (Aldrich), 2 mL, 2 mmol) was added. The reaction mixture was stirred at room temperature for an additional 1 h. Formation of product was confirmed by LC/MS and the product was purified by preparatory HPLC (reverse-phase, acetonitrile/water with 0.1% formic acid) to yield 25 mg (25%) of the title compound. 1H-NMR (400 MHz, d6-DMSO): δ 11.78 (s, 1H), 8.62 (s, 1H), 8.04 (d, 1H), 7.61 (d, 1H), 7.49 (t, 1H), 7.30 (d, 1H), 7.19 (d, 1H), 7.10 (m, 2H), 6.23 (q, 1H), 3.85 (d, 2H), 2.86 (d, 3H), 2.01 (m, 1H), 0.93 (d, 6H). MS (EI) for C22H23N5O2: 390 (MH+).
