Antitubulin Effects of Derivatives of 3-Demethylthiocolchicine, Methylthio Ethers of Natural Colchicinoids, and Thioketones Derived from Thiocolchicine. Comparison with Colchicinoids

Article abstract of DOI:10.1021/jm00164a015

Esterification of the phenolic group in 3-demethylthiocolchicine and exchange of the N-acetyl group with other N-acyl groups or a N-carbalkoxy group afforded many compounds which showed superior activity over the parent drug as inhibitors of tubulin polymerization and of the growth of L1210 murine leukemia cells in culture.A comparison of naturally occuring Colchicum alkaloids with thio isosters, obtained by replacing of the OMe group at C(10) with a SCH3 group, showed the thio ethers to be invariably more potent in these assays.The comparison included3-demethylthiodemecolcine prepared from 3-demethylthiocolchicine by partial synthesis.Thiation of thiocolchicine with Lawesson's reagent afforded novel thiotropolones which exhibited high antitubulin activity.Their structures are fully secured by spectral data.Colchicine and several of its analogues show good antitumor effect in mice infected with P388 lymphocytic leukemia, and all of them show high affinity for tubulin and inhibit tubulin polymerization at low concentration.Consequently, antitubulin assays with this class of compounds can serve as valuable prescreens for the initial evaluation of potential antitumor drugs.