3D-QSAR Study on a Series of Indolo[1,2-b]quinazoline Derivatives with Anticancer Activity and their Molecular Design

Indolo[1,2-b]quinazoline derivatives have recently been reported as a type of compound with potential anticancer activity. On the basis of our the published two-dimensional quantitative structure-activity relationship (2D-QSAR) of these compounds, a further study on the three-dimensional quantitative structure-activity relationship (3D-QSAR) was carried out using the method of comparative molecular field analysis (CoMFA). A reasonable, receivable, and an effective 3D-QSAR model has been established, in which the correlation coefficient (r2) and cross-validation coefficient (q2) values are 0.986 and 0.695, respectively, the statistical squared deviation ratio (F) is 114.6, and the standard deviation (SD) is 0.084. The results suggest that the electrostatic effect of substituent R1 and steric effect of substituent R2 play a very important role in the improvement of the anticancer activity of these compounds. In this article, some significant conclusions, which are in good agreement with the conclusions obtained using 2D-QSAR, were drawn as follows. (1) The electrostatic effect in the substituent R1 part plays a major role, and it is very important to make the first atom of R1 carrying more positive charges in order to improve the anticancer activity of the compounds. (2) The steric effect plays a major role in the substituent R2 part, and the volume of R2 should be moderate. Based on the above conclusions, three new molecules of Indolo[1,2-b]quinazoline derivatives with higher anticancer activity have been theoretically designed and are waiting for support from experiment. The QSAR results can offer a theoretical reference for the pharmaceutical synthesis.