Divulging the regioselectivity of epoxides in the ring-opening reaction, and potential himachalene derivatives predicted to target the antibacterial activities and SARS-CoV-2 spike protein with docking study

Abstract

• α-Himachalene could be a potential drug for SARS-CoV-2. • Bromine atoms located at the epoxy group in compound 8 increased the drug binding affinity. • The attack of the epoxide 1 and 2 by hydride ion H − presented a high regioselectivity. The ring-opening reaction of epoxides 1b and 1c utilizing LiAlH 4 , have been studied within the Molecular Electron Density Theory (MEDT) at the B3LYP/6–31(d) computational level. The regioisomeric reaction paths including the two oxiranes cycles of epoxides 1b and 1c have been explored. DFT calculations show that the attack of the hydride ion H − is favorable on the carbon C 3 for the epoxide 1b, while this action is realized on carbon C 2 for the epoxide 1c in the highest conformity with the experimental outcomes. Furthermore, we have operated a docking calculation to examine the antibacterial activities of the products 1a-1f, further more we have performed a docking calculation to scrutinize the products 1–9 against SARS-CoV-2. Indeed, the docking results showed that α-himachalene ( 2 ) possess a higher affinity to the main protease.