Lithium Hexamethyldisilazide → (8-Cyclopentyl-2-methylsulfanyl-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-6-ylmethyl)-carbamic acid benzyl ester

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Reaction Steps

3-Benzyloxycarbonylamino-propionic acid ethyl ester (6.68 g, 26.58 mmol) was dissolved in tetrahydrofuran (40 mL) to which LiHMDS (28 mL, 28 mmol, 1.0 M in THF) was slowly added. 4-Cyclopentylamino-2-methylsulfanyl-pyrimidine-5-carbaldehyde (3.15 g, 13.29 mmol) was then added neat and the reaction mixture was brought to reflux for 7 hours. The reaction mixture was diluted with ethyl acetate and water, the layers separated, the organic layer dried over MgSO4 and the solvent evaporated to give a crude oil. The crude oil was purified by silica gel chromatography to give (8-cyclopentyl-2-methylsulfanyl-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-6-ylmethyl)-carbamic acid benzyl ester as pale yellow waxy solid (1.67 g, 29.6%). 1H NMR δ(400 MHz, CDCl3) 8.57 (s, 1H), 7.56 (s, 1H), 7.26-7.36 (m, 5H), 5.93 (m, 1H), 5.56 (t, J=6.1 Hz, 1H), 5.08 (s, 2H), 4.25 (d, J=6.2 Hz, 2H), 2.60 (s, 3H), 2.30 (m, 2H), 2.05 (m, 2H), 1.86 (m, 2H), 1.69 (m, 2H).

Provenance & Evidence