A solution of 400 mg (1.44 mM) of 4-chloro-6,7-diethoxy-quinoline-3-carbonitrile and 258 mg (1.88 mM) of 6-Aminoindoline dihydrochloride salt in 10 ml of ethanol was refluxed for 3 hours. To the warm solution was added 1 ml of 1M sodium carbonate and the sample was heated for 5 minutes at 100° C., then poured into 300 ml of ice water. The solid was collected, washed with water followed by ether and dried under vacuum at 80° C. The solid was dissolved in 50/50 methanol/chloroform and dried onto silica gel and purified by chromatography using a gradient of 20% to 50% acetone in hexane to yield 496 mg of the title compound as a tan solid: mass spectrum (electrospray, m/e): M+H 375.1, mp=121-124° C.
