2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → HCID 11687512, compound

Participants

Reaction Steps

2-Benzoyl-6-oxo-1,4,5,6-tetrahydropyridine-3-carboxylic acid methyl ester (5.97 g) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 7.85 g) were stirred together at reflux in toluene (125 ml) for 24 h. More DDQ (7.85 g) was added and the mixture was stirred as before for a further 24 h. The solvent was removed in vacuo, and the residue was purified by flash chromatography on silica gel, eluting with 1:1 ethyl acetate:isohexane, yielding 2-benzoyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid methyl ester as a brown solid (2.07 g). 1H NMR (400 MHz, CDCl3) δ3.54 (3H, s), 6.60 (1H, d, J=9.7 Hz), 7.50 (2H, t, J=7.8 Hz), 7.64 (1H, t, J=7.4 Hz), 7.82 (2H, d, J=8.2 Hz), 7.95 (1H, d, J=9.7 Hz), 11.00 (1H, br s); MS (ES+) m/e 258 [MH]+, 226 [M−OMe]+.

Provenance & Evidence