Phosphorus oxychloride → 5-Chloro-3-(4-methoxybenzyl)-6,8-dimethylpyrido[2,3-d]pyrimidine-4,7(3H,8H)-dione

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Reaction Conditions

Reaction Steps

5-Hydroxy-3-(4-methoxybenzyl)-6,8-dimethylpyrido[2,3-d]pyrimidine-4,7(3H,8H)-dione (10 g, 30.6 mmol, compound 8B) was suspended in phosphorus oxychloride (28 mL, 306 mmol) and heated at 80° C. for 5 hours. The solution was evaporated in vacuo, and the residue taken up in DCM and washed with saturated sodium bicarbonate solution until the neutral pH was observed. The organic layer was dried over magnesium sulfate and evaporated to dryness. The residue was purified by silica chromatography using 1% methanol in DCM as eluent to yield 9.28 g of title compound (89%). [M+H] calc'd for C17H16ClN3O3, 346. found, 346.

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