Convenient and efficient access to tri- and tetra-substituted 4-fluoropyridines via a [3+2]/[2+1] cyclization reaction was written by Tang, Xuejiao;Liu, Kun;Qu, Zeming;Zhan, Junyan;Zhu, Rukui;Teng, Fan;Meng, Lili;Huang, Yanmin;Huang, Chusheng;He, Yimiao;Zhu, Qiang. And the article was included in Chinese Chemical Letters in 2022.COA of Formula: C5H5NO This article mentions the following:
A [3 + 2]/[2 + 1] cycloaddition reaction of gem-difluorocyclopropenes was presented, offering a mild and efficient approach to accessing tri- and tetra-substituted 4-fluoropyridines I [R = Ph, 2-MeC6H4, 6-quinolinyl, etc.; X = COOMe, COOEt, COOBn, etc.] in moderate to good yields with excellent regioselectivity. Multiple synthetic applications, including process-scale reactions, modification of bioactive mols., derivatization reactions and synthesis of the analog of the PKM2 modulator, were subsequently described. In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2COA of Formula: C5H5NO).
Pyridin-4-ol (cas: 626-64-2) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.COA of Formula: C5H5NO