Radical-Based Regioselective C-H Functionalization of Electron-Deficient Heteroarenes: Scope, Tunability, and Predictability was written by O’Hara, Fionn;Blackmond, Donna G.;Baran, Phil S.. And the article was included in Journal of the American Chemical Society in 2013.Reference of 59718-84-2 This article mentions the following:
Radical addition processes can be ideally suited for the direct functionalization of heteroaromatic bases, yet these processes are only sparsely used due to the perception of poor or unreliable control of regiochem. A systematic investigation of factors affecting the regiochem. of radical functionalization of heterocycles using alkylsulfinate salts revealed that certain types of substituents exert consistent and additive effects on the regioselectivity of substitution. This allowed us to establish guidelines for predicting regioselectivity on complex π-deficient heteroarenes, including pyridines, pyrimidines, pyridazines, and pyrazines. Since the relative contribution from opposing directing factors was dependent on solvent and pH, it was sometimes possible to tune the regiochem. to a desired result by modifying reaction conditions. This methodol. was applied to the direct, regioselective introduction of iso-Pr groups into complex, biol. active mols., such as diflufenican (I; R = H → R = iso-Pr) and nevirapine (II; R = H → R = iso-Pr). In the experiment, the researchers used many compounds, for example, Methyl 3-methylpicolinate (cas: 59718-84-2Reference of 59718-84-2).
Methyl 3-methylpicolinate (cas: 59718-84-2) 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. Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.Reference of 59718-84-2