Hydrochloric Acid → HCID 18790699, compound

Participants

Reaction Steps

18 ml of 1N sodium hydroxide solution are added, under an argon blanket, to a stirred mixture, at a temperature in the region of 20° C., of 1.75 g of ethyl 8-(2-ethoxycarbonylethyl)-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-2-carboxylate, 220 ml of dioxane and 60 ml of water and stirring is continued for 6 hours. The reaction mixture is filtered, the solid is washed with 2×20 ml of dioxane and 30 ml of water are added to the solid. The solution obtained is acidified to pH 1 with 1N hydrochloric acid and the precipitate is filtered, washed with 2×30 ml of distilled water and then 2×30 ml of acetone and dried under vacuum (1 mm Hg; 0.13 kPa) in the region of 50° C. 0.9 g of 8-(2-carboxyethyl)-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazine-2-carboxylic acid is obtained in the form of a beige solid melting above 290° C. (1H NMR spectrum in d6-DMSO, T=300 K, δ in ppm (200 MHz): 2.60 (2H, t, J=6 Hz, CH2CO2H), 2.90 (2H, t, J=6 Hz, CH2), 4.00 (2H, s, CH2), 7.25 (1H, d, J=8 Hz, arom. CH), 7.45 (1H, s, arom. CH), 7.78 (1H, d, J=8 Hz, arom. CH), 8.50 (1H, s, imidazole H), 12.5 (3H, s, NHCO and 2CO2H)).

Provenance & Evidence