New bis-isoxazole with monoterpenic skeleton: regioselective synthesis, spectroscopic investigation, electrochemical, and density functional theory (DFT) studies.

A novel bis-isoxazole was synthesized from (R)-Carvone and p-methylbenzaldoxime, via two successive [3+2] cycloaddition reactions (32CA). The newly obtained bis-isoxazole has been fully characterized by HRMS and NMR spectroscopy. The HMBC experiment was performed to determine the stereo and the regioselectivity of the reaction. The electrochemical behavior of the studied compound, in oxidation and reduction processes, was examined using the cyclic voltammetry technique. In addition, the regioselectivity of the [3+2] cycloaddition reaction and the molecular structure of the title compound was performed by density functional theory (DFT). The HOMO and LUMO orbitals were investigated to determine the electronic properties of the synthesized compound. Besides, the global reactivity indexes were used to explain the regioselectivity for the formation of the bis-isoxazole, the theoretical results are in good agreement with experimental findings.