Rhodium-Catalyzed C4-Selective C-H Alkenylation of 2-Pyridones by Traceless Directing Group Strategy was written by Hazra, Sunit;Hirano, Koji;Miura, Masahiro. And the article was included in Organic Letters in 2021.Reference of 59864-31-2 This article mentions the following:
A rhodium-catalyzed C4-selective C-H alkenylation of 3-carboxy-2-pyridones I (R = H, Me, cyclohexyloxy, Ph, piperidin-1-yl, etc.; R1 = H, Me; R2 = Me, Et, n-Bu, Bn) with styrenes R3CH=CH2 [R3 = (cyclohexyloxy)carbonyl, Ph, 2-methylphenyl, etc.] has been developed. The carboxylic group at the C3 position works as the traceless directing group, and the corresponding C4-alkenylated 2-pyridones II are obtained exclusively with concomitant decarboxylation. Unlike the reported procedures, the exclusive C4 selectivity is uniformly observed even in the presence of potentially more reactive C-H bonds at the C5 and C6 positions. By using this strategy, multiple substituted 2-pyridone III can be prepared via sequential C-H functionalization reactions. In the experiment, the researchers used many compounds, for example, 1-Methyl-6-oxo-1,6-dihydropyridine-2-carboxylic acid (cas: 59864-31-2Reference of 59864-31-2).
1-Methyl-6-oxo-1,6-dihydropyridine-2-carboxylic acid (cas: 59864-31-2) belongs to pyridine derivatives. Pyridine has a conjugated system of six 闂?electrons that are delocalized over the ring. The molecule is planar and, thus, follows the H闂佹椿浜滈妴鍗l criteria for aromatic systems. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C闂備胶鍋ㄩ崕鎻掝嚕?in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Reference of 59864-31-2