Oxalyl chloride → 5,6-Dihydro-4H-pyrrolo[3,2,1-ij]quinoline-1,2-dione

Participants

Reaction Steps

To a solution of 1,2,3,4-tetrahydroquinoline (18.5 g) in anhydrous tetrahydrofuran (THF; 150 ml) was added a solution of oxalyl chloride (22 ml) in anhydrous THF (100 ml) dropwise under reflux and reflux was continued for 3.5 hours. After cooling, the reaction mixture was concentrated under reduced pressure. To the resulting residue was added carbon disulfide (800 ml) and refluxed under stirring. To the refluxing mixture was added aluminum chloride (35 g) portionwise during 5 hours, further refluxed for 3 hours and then allowed to stand for overnight. To the reaction mixture, under cooling, was added concentrated hydrochloric acid (150 ml) and then water (150 ml), extracted with chloroform. The organic layer was washed with water, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting residue was recrystallized from ethanol to give the title compound (21 g, 80%) as dark reddish needles, mp 198°-200 ° C.

Provenance & Evidence