1,8-Diazabicyclo(5.4.0)undec-7-ene → 8-cyclohexyl-5-hydroxy-2-methylsulfanyl-8H-pyrido[2,3-d]pyrimidin-7-one

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Reaction Conditions

Reaction Steps

DBU (11.05 mL) was added dropwise, under argon atmosphere, to a mixture of 3-(4-cyclohexylamino-2-methylsulfanyl-pyrimidin-5-yl)-3-oxo-propionic acid ethyl ester (21.5 g) and DIPEA (85 mL), and the resulting mixture heated at 125° C. for 1 h, then stirred at RT overnight. The volatiles were evaporated under reduced pressure, and the residue was diluted with EtOAc and HCl (1 M aq). The solid residue was collected by filtration, the organic layer was separated, and the aqueous layer was extracted 3× with EtOAc. The combined organic extracts were dried over Na2SO4, filtered and evaporated under reduced pressure. The combined solids were washed 3× with NaHSO4 (aq 10%), twice with water, hexane (8×100 mL), and a 2:1 mixture of hexane and EtOAc (4×100 mL) to give, after drying under reduced pressure, 19.9 g (99% yield) of 8-cyclohexyl-5-hydroxy-2-methylsulfanyl-8H-pyrido[2,3-d]pyrimidin-7-one without further purifications.

Provenance & Evidence