A Theoretical Study on the Mechanism of Quinoxaline Cholestane Formation

The present article describes a theoretical study of the reaction mechanism involved in the conversion of cholest-4-en-3-one to 5α-cholest-3-eno-[3,4-b] quinoxaline. In this study, the reaction proceeded via condensation, cyclization, and oxidation. The reaction pathway was characterized using Frontier Molecular Orbital analysis and a comparison of relative energies, which were computed using the theoretical approach of Density Functional Theory with the B3LYP/6-31G(d) method. The reaction involved a total of six intermediates and three transition states. The energy barriers of the transition states were also reported. It was determined that, overall, the reaction was an endothermic reaction. The stability of all the structures was confirmed by calculating their respective fundamental frequencies and energy minima. Moreover, these findings have implications for the design of novel steroid derivatives and may aid in the development of synthetic routes for biologically active molecules involving quinoxaline frameworks.