To a suspension of 2-(2-cyclopropylbenzoimidazol-1-yl)-9-methyl-6-morpholin-4-yl-9H-purine-8-carbaldehyde (500 mg, 1.24 mmol) in EtOH (16 mL) was added AgNO3 (265 mg, 1.56 mmol) followed by a solution of NaOH (302 mg, 7.5 mmol) in H2O (5 mL). The resulting black suspension was allowed to stir at r.t. for 30 min then filtered through Celite® and the resulting filtrate concentrated in vacuo. The resulting residue was dissolved in H2O and basified by the addition of aq. NaOH. The aqueous phase was extracted with DCM then acidified to pH 2 with HCl. The aqueous phase was concentrated in vacuo to half volume then cooled on ice. The resulting precipitate was collected by filtration and dried in vacuo affording the title compound (280 mg, 55%).—1H NMR (DMSO, 400 MHz): δ 8.12-8.11 (1 H, m), 7.72-7.68 (1 H, m), 7.44-7.43 (2 H, m), 4.60 (4 H, brd s), 4.04 (3 H, s), 3.90-3.70 (4 H, m), 3.06-3.00 (1 H, m), 1.33-1.31 (4 H, m)
