1-Methoxy-2-propanol → 5-[5-Acetyl-2-(2-methoxy-1-methylethoxy)-3-pyridinyl]-3-ethyl-2-(2-methoxyethyl)-2,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one

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Reaction Steps

5-(5-Acetyl-2-butoxy-3-pyridinyl)-3-ethyl-2-(2-methoxyethyl)-2,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (Example 16) (150 mg, 0.36 mmol) was dissolved in 1-methoxypropan-2-ol (3 mL) and the solution heated at reflux for 5 minutes to degas the solution. After cooling potassium hexamethyldisilazide (360 mg, 1.80 mmol) was added and the solution reheated to reflux for 8 h. The cooled reaction mixture was evaporated to dryness and partitioned between ethyl acetate and water after 1N hydrochloric acid had been used to adjust the pH to 8. The organic phase was separated and washed with brine, dried (MgSO4) and evaporated. The crude product was purified by flash column chromatography (gradient elution from 100% dichloromethane 0.5% ammonia to 99% dichloromethane:1% methanol:0.5% ammonia) to give the title compound (45 mg, 29%).

Provenance & Evidence