Hydroquinone → HCID 69733596, compound

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Reaction Steps

A solution of (R)-3-(5-acetoxyhexyl)-6-amino-1-methyluracil (3.0 g, 10.6 mmol), diketene (1.2 ml, 15.9 mmol), hydroquinone (50 mg, 0.45 mmol) and dichloroethane (100 ml) was heated at reflux for 36 hours. After cooling to room temperature, the solution was washed with water, dried over sodium sulfate, and concentrated under vacuum. The residue was purified by column chromatography on silica gel eluting with 20% ethyl acetate-toluene followed by 50% ethyl acetate-toluene) to provide (R)-3-(5-acetoxyhexyl)-1,7-dimethylpyrido[2,3-d]pyrimidine-2,4,5(1H,3H,8H)-trione (1.45 g, 39% yield) followed by (R)-3-(5-acetoxyhexyl)-1,5-dimethylpyrido[2,3-d]pyrimidine-2,4,7(1H,3H,8H)-trione (1.26 g, 34% yield). 1H NMR (300 MHz, CDCl3) δ 1.17 (d, 3H), 1.28-1.67 (m, 6H), 1.99 (s, 3H), 2.67 (s, 3H), 3.59 (s, 3H), 3.95 (t, 2H), 4.85 (sextet, 1H), 6.23 (s, 1H). 13C NMR (75 MHz, CDCl3) δ 19.65, 21.16, 22.58, 22.74, 27.31, 29.87, 35.25, 41.34, 70.88,100.16, 109.56, 150.05, 150.49, 156.07,160.41, 164.03,171.07.

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