Computer-assisted structure-activity correlations

Several types of Michael acceptors, including alpha,beta-unsaturated ketones, lactones, and lactams, have been extensively studied as potential anticancer agents. A concerted effort was made to explore the relationship between the structures of these compounds and their antitumor activity against P388 and L1210 leukemias. This article describes the computer-assisted structure-activity evaluation of more than 14,000 compounds, representing different classes of Michael acceptors, in the NCI file. In this study, advantage has been taken of the computer's ability to search substructures according to precise definitions and to manipulate these substructures utilizing Boolean logic. Olefinic conjugated Michael-type acceptors, e.g., styrenes with different activating groups, cinnamic acid derivatives, and alpha,beta-unsaturated nitro, cyano, sulfone, sulfoxide, and acetylenic compounds, have shown appreciable activity against P388 lymphocytic leukemia. The analysis of lactones and lactams includes substructures representing a wide variety of exocyclic and endocyclic alpha,beta-unsaturated compounds. The analysis describes the effect of certain groups, such as an --OH, --OR, alpha,beta-unsaturated ester, or epoxide, adjacent to the alpha,beta-unsaturated center, on the antitumor activity of these compounds. A combination of one or more of these activating groups with an alpha-methylene-gamma-lactone moiety significantly enhanced the activity against P388. In general, many of the classes of compounds studied have shown poor activity against the more stringent L1210 lymphoid leukemia.