Ruthenium-catalyzed Regioselective C-2 Alkenylation of Naphthalimide-benzothiazole Conjugates

Abstract

We have developed a highly regioselective [RuCl 2 (p-cymene)] 2 catalyzed directing group assisted C2-alkenylation of 1,8-naphthalimide and benzothiazole conjugate in which imide is acting as a weak directing group. The imide group forms the coordination bond with Ru metal, and then transition metal-assisted C-H activation occurs at the proximal C-H bond. Here, we have synthesised the hybrid of two biological active moieties, i.e., 1,8- naphthalimide and benzothiazole. The benzothiazole ring attached to the C-4 position of 1,8- naphthalimide increases the electron density at a particular phenyl ring, which favours selective monoalkenylation at the C2 position in good yields. The optimization of reactions was done with different types of catalysts, additives, oxidants, and solvents at different temperatures with varied reaction time.