Acetic Acid → 1-Isopropyl-2-oxo-1,2-dihydro-3-quinolinecarboxylic acid

Participants

Reaction Conditions

Reaction Steps

2,2-Dimethyl-[1,3]dioxane-4,6-dione, commonly Meldrum's acid, (166.9 g, 1.16 mol) was added to a stirred solution of 2-isopropylaminobenzaldehyde (105 g, 0.64 mol), acetic acid (73.6 mL, 1.29 mol) and ethylenediamine (43.0 mL, 0.64 mol) in methanol (1 L) at 0° C. The reaction mixture was stirred for 1 h at 0° C. and then at room temperature overnight. The resulting suspension was filtered and the solid washed with methanol and collected to yield the title intermediate, 1-isopropyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid (146 g, 98%) as an off-white solid. 1H NMR (CDCl3; 300 MHz): 1.72 (d, 6H, CH(CH3)2), 5.50 (bs, 1H, CH(CH3)2), 7.44 (t, 1H, ArH), 7.75-7.77 (m, 2H, ArH), 7.82 (d, 1H, ArH), 8.89 (s, H, CH).

Provenance & Evidence