Ethyl 2,4-dimethyl-6-oxo-1-phenyl-1,6-dihydropyridine-3-carboxylate → 2,4-Dimethyl-6-oxo-1-phenyl-1,6-dihydropyridine-3-carboxylic acid

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Reaction Steps

A mixture of 2,4-dimethyl-6-oxo-1-phenyl-1,6-dihydro-pyridine-3-carboxylic acid ethyl ester (108 mg, 0.398 mmol) in methanol (0.8 mL) and 32% aq. NaOH (0.25 mL) was shaken at 60° for 22 hrs (after 5 hours only 70% conversion was observed). The reaction mixture was quenched with water (5 ml), extracted with ether (3×2 ml), and acidified 3M HCl (1 mL, pH=0). The title compound was separated by filtration to give 52.1 mg of colorless solid, yield 54%. LC-MS (m/z) 244.5 (MH+); tR=0.54. 1H NMR (600 MHz, DMSO-d6): 1.94 (s, 3H, 2-Me), 2.19 (d, J=0.9 Hz, 3H, 4-Me), 6.29 (s, 1H, 5-H), 7.25 (dm, J=7.7 Hz, J<1.5 Hz, 2H, two ortho-H of Ph), 7.47 (tt, J=7.4 Hz, J=1.2 Hz, 1H, para-H of Ph), 7.53 (tm, J=7.5 Hz, J<1.7 Hz, 2H, two meta-H of Ph), 13.26 (br. s, 1H, CO2H).

Provenance & Evidence