Sodium (414 mg) was dissolved in ethanol (30 ml) and 1-cyclopentyl-3-ethyl-5-amino-1H-pyrazole-4-carboxamide (2.0 g) and methyl 4-[2-(4-morpholinyl)ethoxy]phenylacetate (5.03 g, 18 mmol) were added. The reaction mixture was refluxed overnight, the solvent was stripped, water was added to the residue, followed by sufficient acetic acid to adjust the pH to 8-9. An oil separated which was collected by decantation and treated with water and saturated NaHCO3. The mixture was extracted with ethyl acetate and washed with water and then saturated NaHCO3 (2×). The aqueous layer was extracted with additional ethyl acetate and the combined organic layers were washed with 2N NaOH and brine. The organic layer was dried over MgSO4, filtered and stripped to afford crude product which was digested with ether and collected by filtration. The crude product was purified by several acid/base work-ups, followed by recrystallization from ether to afford 1.67 g of 1-cyclopentyl-3-ethyl-6-[4-[2-(4-morpholinyl)ethoxy]phenylmethyl]pyrazolo[3,4-d]pyrimidin-4-one, m.p. 136-137° C.
