A solution of ethyl 1-cyclopropyl-8-(4-methylphenyl)-9-methyl-4-oxo-4H-quinolizine-3-carboxylate (90 mg, 0.249 mmol) in THF (6 mL) and water (2 mL) was treated with LiOH (43 mg, 1.02 mmol). The reaction was heated to 60° C. for 2 h and acidified with 1N HCl to pH 4. The precipitate was dissolved with ethyl acetate (20 mL) and washed with brine (20 mL). The organic phase was separated, dried, and concentrated. The precipitate was filtered to afford the title compound EXAMPLE 33 as a yellow solid (65 mg, 78%). ESI-MS m/z: 334 (M+H)+; 1H NMR (300 MHz, DMSO-d6) δ ppm: 9.31 (d, J=7.2 Hz, 1H), 8.24 (s, 1H), 7.54 (d, J=7.2 Hz, 1H), 7.44 (d, J=7.2 Hz, 2H), 7.38 (d, J=7.2 Hz, 2H), 2.84 (s, 3H), 2.54-2.52 (m, 1H), 2.39 (s, 3H), 1.06-1.03 (m, 2H), 0.77-0.75 (m, 2H).
