5-[2-Ethoxy-5-(4-ethylpiperazin-1-ylsulphonyl)pyridin-3-yl]-3-ethyl-2-methyl-2,6-dihydro-7h-pyrazolo[4,3-d]pyrimidin-7-one → 3-Ethyl-5-[5-(4-ethylpiperazin-1-ylsulphonyl)-2-methoxypyridin-3-yl]-2-methyl-2,6-dihydro-7h-pyrazolo[4,3-d]pyrimidin-7-one

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Reaction Conditions

Reaction Steps

A mixture of the title compound of Example 78 (100 mg, 0.21 mmol), and copper (II) sulphate heptahydrate (75 mg, 0.3 mmol) in saturated methanolic ammonia (20 ml) was heated at 100° C. for 4 hours in a sealed vessel. The cooled mixture was evaporated under reduced pressure and the residue suspended in aqueous sodium carbonate solution (20 ml) and extracted with dichloromethane (3×20 ml). The combined organic extracts were washed with brine (3×20 ml), dried (Na2SO4) and evaporated under reduced pressure to give a green solid. The crude product was purified by column chromatography on silica gel, using an elution gradient of dichloromethane: methanol (100:0 to 97:3) and recrystallised from hexane/ethyl acetate/methanol to afford the title compound (23 mg, 24%) as a white solid. Found: C, 51.22; H, 5.81; N, 20.61. C20H27N7O4S:0.5H2O requires C, 51.05; H, 6.00; N, 20.84% δ (CDCl3): 1.07 (3H, t), 1.40 (3H, t), 2.40-2.65 (6H, m), 3.04 (2H, q), 3.19 (4H, m), 4.09 (3H, s), 4.24 (3H, s), 8.65 (1H, s), 9.05 (1H, s), 10.58 (1H, s). LRMS: m/z 462 (M+1)+

Provenance & Evidence