(-)-2-Butanol → 3-Ethyl-5-[5-(4-ethylpiperazin-1-ylsulphonyl)-2-(1(r)-methyl-n-propoxy)pyridin-3-yl]-2-methyl-2,6-dihydro-7h-pyrazolo[4,3-d]pyrimidin-7-one

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The title compound of Example 78 (400 mg, 0.84 mmol) was added to a mixture of potassium bis(trimethylsilyl)amide (840 mg, 4.2 mmol) in (R)-2-butanol (4 ml) and the mixture stirred at 110° C. for 18 hours. The cooled mixture was concentrated under reduced pressure and the residue suspended in water (10 ml) and neutralised using 2N hydrochloric acid. This aqueous suspension was extracted with ethyl acetate (3×30 ml), the combined organic extracts washed with sodium hydroxide solution (20 ml), brine (2×30 ml), dried (Na2SO4) and evaporated under reduced pressure. The crude product was purified by column chromatography on silica gel, using an elution gradient of dichloromethane:methanol (100:0 to 97.5:2.5) and the product suspended in ether and evaporated under reduced pressure. This solid was recrystallised from hexane/ethyl acetate to afford the title compound (72 mg, 17%) as a white solid.

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