Triethylamine → 4-Oxo-1,4-dihydro-2,5-quinolinedicarboxylic acid 2-ethyl 5-methyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of 24 (4.50 g, 14.5 mmol) in EtOAc (100 mL) was added Et3N (50 mL). The reaction mixture was heated to 50° C. to generate a clear solution. 10% Pd/C (0.500 g) was added carefully. The reaction mixture was hydrogenated (50 psi) on a Parr hydrogenation apparatus at room temperature for 4 h. Then the catalyst was filtered off on a pad of celite and the filtrate washed with water (100 mL). The aqueous layer was extracted with EtOAc (100 mL) and the combined organic layers were dried (MgSO4), filtered, and concentrated. The crude residue was washed with Et2O (100 mL) to give an off-white solid (29, 3.46 g, 99.1%). 1H NMR (DMSO-d6, 300 MHz) δ ?8.05 (d, J=8.6 Hz, 1H), 7.75 (t, J=8.6 Hz, 1H), 7.29 (d, J=8.6 Hz, 1H), 6.63 (s, 1H), 4.44 (q, J=7.3 Hz, 2H), 3.80 (s, 3H), 1.37 (t, J=7.3 Hz, 3H).

Provenance & Evidence