Acetophenone → 2-Phenyl-[1,6]naphthyridine-4-carboxylic acid

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Reaction Conditions

Reaction Steps

[4-(2,2-Dimethyl-propionylamino)-pyridin-3-yl]-oxo-acetic acid ethyl ester (532 mg, 1.91 mmol) was taken up in ethanol (1.9 mL) and 4N KOH (1.9 mL, 4 equiv) was added. The solution was refluxed for 2-3 h at 100° C., acetophenone (0.446 mL, 2.0 equiv) was added neat, and the reaction was allowed to reflux overnight. Upon cooling to room temperature, the solution was diluted with 1N NaOH and extracted twice with ether. The product was precipitated from the aqueous layer by the addition of glacial AcOH (5-10 mL). The solids were collected by vacuum filtration, rinsed with cold water, and dried under high vacuum (white solid, 371 mg, 78%). 1H NMR (400 MHz, DMSO-d6) δ 10.00 (s, 1 H), 8.80 (d, J=5.6 Hz, 1 H), 8.56 (s, 1 H), 8.35-8.31 (m, 2 H), 8.03 (d, J=6.0 Hz, 1 H), 7.61-7.58 (m, 3 H). MS (LR-APCI) calcd. for C15H11N2O2 (M+H) 251.1; found 251.5.

Provenance & Evidence