The author of 《Pyrimidines. XLIII. Ring transformations in reactions of heterocyclic compounds with nucleophiles. IX. Conversion of N-methylpyrimidinium salts to pyridines by carbanions》 were Oostveen, E. A.; Van der Plas, H. C.. And the article was published in Recueil des Travaux Chimiques des Pays-Bas in 1974. Reference of 2-Oxo-5-phenyl-1,2-dihydropyridine-3-carboxylic acid The author mentioned the following in the article:
On treatment with active methylene compounds in basic media the quaternary pyrimidinium salts were converted into pyridine derivatives. Thus, I(R = R1 = H; R = Ph, R1 = H, R = H, R1 = Ph) and CH2(CO2Et) with NaOH gave II. In the experiment, the researchers used many compounds, for example, 2-Oxo-5-phenyl-1,2-dihydropyridine-3-carboxylic acid(cas: 10177-08-9Reference of 2-Oxo-5-phenyl-1,2-dihydropyridine-3-carboxylic acid)
2-Oxo-5-phenyl-1,2-dihydropyridine-3-carboxylic acid(cas: 10177-08-9) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. Reference of 2-Oxo-5-phenyl-1,2-dihydropyridine-3-carboxylic acid Pyridine has a conjugated system of six π electrons that are delocalized over the ring.