To a solution of trans-3-(4-amino-3-methoxyphenyl)-1-[4-(4-methylpiperazino)cyclohexyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine (500 mg, 1.15 mmol) in pyridine (5 ml) was added 4-(dimethylamino)benzoylchloride (420 mg, 2.28 mol) dropwise. The solution was stirred overnight, the solvent evaporated and the residue partitioned between dichloromethane and 2N NaOH solution. The aqueous layer was extracted with dichloromethane (×3). The organics were dried, filtered and evaporated to leave a solid which was triturated with EtOAc/Et2O (1:4) to leave a solid which was dissolved in EtOAc and treated with maleic acid (3 eqs.) to give trans-N1-(4-{4-amino-1-[4-(4-methylpiperazino)cyclohexyl]-1H-pyrazolo[3,4-d]pyrimidin-3-yl}-2-methoxyphenyl)-4-(dimethylamino)benzamide (320 mg, 30%). 1H NMR (d6-DMSO)): δ H 9.05 (1H, s), 8.25 (1H, s), 8.18 (1H, d, J=8 Hz), 7.84 (2H, d, J=9.2 Hz), 7.29 (1H, s), 7.25 (1H, d, J=8 Hz), 6.78 (2H, d, J=8.8 Hz), 6.17 (6H, s), 4.71 (1H, m), 3.95 (3H, s), 3.01 (6H, s), 2.83-3.18 (9H, m), 2.68 (3H, s), 2.08 (6H, m), 1.56 (2H, m). HPLC (5.23 mins, 100%)
