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

Participants

Reaction Steps

To the refluxing mixture of oxalyl chloride (22 ml) in dry tetrahydrofuran (THF, 100 ml) was added 1,2,3,4-tetrahydroquinoline (18.5 g) in dry THF (150 ml) dropwise. The mixture was refluxed for 3.5 hours after addition was completed, then cooled to room temperature and concentrated under reduced pressure. The residue was dissolved in carbon disulfide (800 ml) and heated up to reflux. To the refluxing mixture was added aluminum chloride (35 g) portionwise over 5 hours period under stirring. The reaction mixture was refluxed for an additional 3 hours and allowed to stand for overnight at room temperature. After decantation of the solvent, the residue, cooled by an ice bath, was treated with water (150 ml). The mixture was extracted with chloroform and washed with water and dried over anhydrous sodium sulfate. Evaporation of chloroform afforded the title compound. The compound was recrystallized from ethanol to give 21 g (80%) of dark red needles, mp 198°-200° C.

Provenance & Evidence