question: Chloroquine was theoretically reacted with the coumarin compound Two compounds viz [N-(7-chloroquinolin-4-yl)-N-(5-(diethylamino)pentan-2-yl)-4-methyl-2-oxo-2H-chromene-7-sulfonamide] (3) and [N-(7-chloroquinolin-4-yl)-N-(5-(diethylamino)pentan-2-yl)-4-methyl-2-oxo-2H-chromene-6-sulfonamide] (4) were suggested The results showed that compound 4 may influence the COVID-19 treatment The physico-chemical parameters were determined through theoretical calculations by using Hartree-Fock at different basis sets (6-31G), (STO/3G) and the semi-empirical (AM1) method The calculations demonstrated the scheme of reaction between coumarin and the chloroquine structure by using the predicted mechanisms The physical and chemical properties of the predicted compounds were determined to select the optimal form as the candidate for COVID-19 treatment Compound 4 was more stable than compound 3, with different proteins viz 6YHU, 6YI3 and 6LU7 Three types of software, including Gaussian 03, Chem-Bio office and molecular operating environment (MOE) were employed © This is an open access journal, and articles are distributed under the terms of the Attribution 4 0 International (CC BY 4 0) License This license lets others distribute, remix, tweak, and build upon your work, even commercially, as long as they credit the author for the original creation You must give appropriate credit, provide a link to the license, and indicate if changes were made