Structure-function studies with derivatives of 6-benzyl-1,3-benzodioxole, a new class of synthetic compounds which inhibit tubulin polymerization and mitosis

A new class of synthetic antineoplastic compounds, derivatives of 6-benzyl-1,3-benzodioxole, has significant antimitotic activity. These compounds inhibit microtubule assembly and are competitive inhibitors of the binding of colchicine to tubulin. Both their structure and their partial inhibition of tubulin-dependent GTP hydrolysis indicate that they are most comparable to podophyllotoxin of all known antimitotic drugs. Maximum activity required an intact dioxole ring, a methoxy or ethoxy substituent at position 5, and, on the benzyl moiety at position 6, a para-methoxy group. Additional methoxy groups on the benzyl substituent, to increase the apparent structural similarity to podophyllotoxin, resulted in major reduction of the antitubulin activity of these drugs.