N-methyl-2-pyrrolidone → tert-butyl 4-(4-cyanophenyl)-3,4-dihydroquinoxaline-1(2H)-carboxylate

Participants

Reaction Steps

1 g of 3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester, 10 ml of N-methylpyrrolidinone, 0.57 g of 4-fluorobenzonitrile and 0.96 g of potassium tert-butoxide are introduced into a 20 ml glass tube. The reaction medium is stirred for 5 min, water is added and extraction is carried out 3 times with diethyl ether. The organic phases are combined, washed with water and then with a saturated aqueous sodium chloride solution, dried over sodium sulfate and concentrated under reduced pressure. The residue is chromatographed on silica gel eluted with a gradient of ethyl acetate from 3.5% to 35% in heptane. 0.9 g of tert-butyl 4-(4-cyanophenyl)-3,4-dihydroquinoxaline-1(2H)-carboxylate is obtained.

Provenance & Evidence