N-bromobutanimide → 6-bromomethyl-8-cyclopentyl-2-methylsulfanyl-8H-pyrido[2,3-d]pyrimidin-7-one
Reaction equation
[CH:1]1([N:6]2[C:11]3[N:12]=[C:13]([S:16][CH3:17])[N:14]=[CH:15][C:10]=3[CH:9]=[C:8]([CH3:18])[C:7]2=[O:19])[CH2:5][CH2:4][CH2:3][CH2:2]1.[Br:20]N1C(=O)CCC1=O>C(Cl)(Cl)(Cl)Cl>[Br:20][CH2:18][C:8]1[C:7](=[O:19])[N:6]([CH:1]2[CH2:2][CH2:3][CH2:4][CH2:5]2)[C:11]2[N:12]=[C:13]([S:16][CH3:17])[N:14]=[CH:15][C:10]=2[CH:9]=1Participants
4
Procedure
8-Cyclopentyl-6-methyl-2-methylsulfanyl-8H-pyrido[2,3-d]pyrimidin-7-one (3.5 g, 12.7 mmol) and N-bromosuccinimide (2.6 g, 14.6 mmol) in carbon tetrachloride (100 ml) were irradiated with ultraviolet light allowing the temperature to reach 45° C. over 3 hours. The mixture was filtered, washed with dilute sodium sulfite solution, then brine, and dried over anhydrous magnesium sulfate. The crude product was chromatographed on silica gel eluting with 1:1 ethyl acetate:hexane to provide 6-bromomethyl-8-cyclopentyl-2-methylsulfanyl-8H-pyrido[2,3-d]pyrimidin-7-one as a crystalline solid yielding (1.46 g, 32% yield), mp 103-105° C.