Hydrochloric Acid → HCID 14842724, compound

Participants

Reaction Steps

3-Cyanoaniline (21.3 g, 0.18 mol) and dimethylacetylene dicarboxylate (10.9 ml, 0.12 mol) were dissolved in dry methanol and heated at reflux for 14 h. After cooling, the solvent was removed in vacuo and the residue partitioned between diethyl ether and 1N hydrochloric acid. The organic layer was dried (Na2SO4), filtered and concentrated in vacuo to leave an oil which was heated in diphenyl ether (100 ml) at 250° C. for 15 minutes. On cooling, a solid precipated which was collected and recrystallised successively from acetic acid/diethyl ether, then from pyridine, to give a pure material by t.l.c. (0.165 g). This was dissolved in water (20 ml) and methanol (10 ml) with sodium hydroxide (0.13 g) and the solution heated at 100° C. for 2 h. Addition of 1N hydrochloric acid caused precipitation of a white solid which was collected by filtration and washed successively with water, ethanol and diethyl ether to give 5-cyano-4-oxo-1,4-dihydroquinoline-2-carboxylic acid (0.14 g) m.p. 278°-279° C., δ (360 MHz, NAOD) 6.96 (1H, s, 3-H), 7.64 (1H, dd, 7-H), 7.83 (1H, dd, 6-H) and 8.05 (1H, dd, 8-H). (Found: C, 60.23; H, 3.03; N, 12.46%. C11H6N2O3. 0.3H2O requires C, 60.17; H, 3.03; N, 12.78%).

Provenance & Evidence