1,1'-Biphenyl, mixt. with 1,1'-oxybis(benzene) → 1-(4-Hydroxy-6-methoxy-1,5-naphthyridin-3-yl)ethanone

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Reaction Steps

To a flask containing Dowtherm™ A (500 mL) at 250° C. was added ethyl 2-[(6-methoxypyridin-3-ylamino)methylene]-3-oxobutanoate (75 g, 0.28 mol) portion wise over 3 to 5 min and the reaction mixture was stirred for an additional 30 to 60 min. The reaction mixture was removed from the heat source, cooled to room temperature and diluted with hexanes to facilitate precipitation. The solids were filtered, washed with hexanes and acetonitrile and dried under vacuum to afford the desired product (60 g, 46%) as an off-white solid: 1H NMR (500 MHz, DMSO-d6) δ 12.48 (bs, 1H), 8.45 (d, J=5.2 Hz, 1H), 8.00 (d, J=8.9 Hz, 1H), 7.40-7.37 (m, 1H), 7.21 (d, J=8.9 Hz, 1H), 7.01-6.99 (m, 1H), 3.96 (s, 3H), 2.61 (s, 3H); ESI MS m/z 219 [M+H]+.

Provenance & Evidence