Hydrochloric Acid → HCID 19870590, compound

Participants

Reaction Steps

A mixture of E,E-indole-3,6-diacrylic acid (1 g), 4-dimethylaminopyridine (1.19 g), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1.86 g) and pyrrolidine (0.69 g) was dissolved in N,N-dimethylformamide (35 ml), and stirred under an atmosphere of nitrogen. Additional portions (10% by weight) of each of the reagents were added at the end of each 24 hour period (five times) until TLC monitoring indicated completion of the reaction after 6 days. The mixture was added slowly to vigorously-stirred 2M hydrochloric acid (100 ml); the precipitate was isolated by filtration, washed with water and dried under vacuum to give E,E-3,6-di(3-oxo-3-pyrrolidino-1-propenyl)indole (0.98 g, 69%) as a yellow powder; mp 268°-270° C.; partial NMR (250 MHz, DMSO-d6): 1.70°-2.02 (m, 8H, pyrrolidino H), 3.41(m, 4H, pyrrolidino H), 3.66(m, 4H, pyrrolidino H); 6.75(d, J=15.6 Hz, 1H, olefinic H); 6.94(d, J=15.5 Hz, 1H, olefinic H); 11.76(br s, 1H, NH-indole).

Provenance & Evidence