Pyridine → Des-(2-cyclohexane-1,3-dione) Fenquinotrione Ethyl Ester

Participants

Reaction Steps

To a slurry containing 5.7 g (22.6 mmol) of ethyl 5-chloro-2-oxo-1,2-dihydroquinoxaline-3-carboxylate, 6.9 g (45.4 mmol) of 4-methoxyphenylboric acid, 8.2 g (45.1 mmol) of anhydrous copper (II) acetate and chloroform (200 ml), 3.6 g (45.5 mmol) of pyridine and 4.6 g (45.5 mmol) of triethylamine were added dropwise, and the mixture was stirred for 72 hours at room temperature. The reaction mixture was washed with 10% hydrochloric acid, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue thus obtained was isolated by silica gel chromatography (developing solvent: ethyl acetate:hexane=2:3), and the isolated solid was washed with diisopropyl ether, to obtain 6.3 g (yield: 78%) of ethyl 5-chloro-1-(4-methoxyphenyl)-2-oxo-1,2-dihydroquinoxaline-3-carboxylate as a pale yellow powder.

Provenance & Evidence