Triethylamine → 3-(1,6-dimethyl-1H-indol-3-yl)-4-(1-methyl-1H-indol-3yl)-pyrrole-2,5-dione

Participants

Reaction Conditions

Reaction Steps

To a suspension of the known (1-methyl-1H-indol-3-yl)-oxo-acetyl chloride (183 mg, 0.83 mm) and 2-(1,6-dimethyl-1H-indol-3-yl)-acetimidic acid isopropyl ester hydrochloride (233 mg, 0.83 mm) in CH2Cl2 (6 mL) which had been cooled to 0° C., was added Et3N (0.46 mL, 3.3 mm). The reaction was allowed to warm to room temperature overnight, then diluted with CH2Cl2 (20 mL), and extracted with H2O(15 mL) and 0.5N HCl(15 mL). The organic fraction was dried over MgSO4, filtered and evaporated, and the residue combined with toluene (3 mL). After cooling to 0° C., para-toluene sulfonic acid (pTsOH) (174 mg, 0.91 mm) was added, and the mixture was stirred at room temperature for 3 hours. The red solids which precipitated were collected and partitioned between CH2Cl2 (50 mL) and H2O(25 mL). The organic fraction was washed with saturated NaHCO3 (25 mL) solution, then dried over MgSO4, filtered and evaporated. The residue was washed with cold CH2Cl2 to yield 3-(1,6-dimethyl-1H-indol-3-yl)-4-(1-methyl-1H-indol-3yl)-pyrrole-2,5-dione; mp=264°-266° C.

Provenance & Evidence