A mixture of 2 g (5.2 mm) of 2-pivaloylamino-4-hydroxy-6-(3-tetrahydropyr-2-yloxyprop-1-yn-1-yl)-pyrido[2,3-d]pyrimidine, 40 ml of methanol, 20 ml of chloroform, 40 mg of 5% palladium on barium sulfate, and 40 mg of synthetic quinoline was stirred under 1 atm hydrogen pressure for 40 min. The solvent then was removed by evaporation and the residue diluted with methylene chloride. The methylene chloride solution was filtered through silica gel with 2% methanol in methylene chloride to remove catalyst and the filtrate then concentrated to give an oil which upon adding ether yielded 1.74 g (86.6%) of 2-pivaloylamino-4-hydroxy-6-(3-tetrahydropyr-2-yloxyprop-1-en-1-yl)-pyrido[2,3-d]pyrimidine as yellow crystals which was further purified through column chromatography eluting with ethyl acetate and recrystallization using ethyl acetate. mp 166°-167° C. Analysis: Calculated for C20H26O4N4 : C, 62.16; H, 6.78; N, 14.50. Found: C, 62.30; H, 6.88; N, 14.74. NMR (CDCl3), delta, 1.35 (s, 9H), 1.54-1.88 (m, 6H), 3.51-3.58 (m, 1H), 3.85-3.93 (m, 1H), 4.26-4.33 (m, 1H), 4.51-4.57 (m, 1H), 4.70 (t, 1H, J=3.4 Hz), 6.07-6.15 (m, 1H), 6.62 (d, 1H, J=12.1 Hz), 8.35 (brs, NH), 8.37 (d, 1H, J=2.5 Hz), 8.79 (d, 1H, J=2.5 Hz), 12.7 (brs, NH).
