Divergent synthesis and antitumour activity of novel conformationally constrained (−)-muricatacin analogues

Abstract

Four novel conformationally restricted (?)-muricatacin analogues, bearing a methoxy group at the C-5 position and with an alkoxymethyl group ?s the C-7 side chain, have been synthesised and their in vitro antiproliferative activity was evaluated against a panel of seven human tumour cell lines, as well as a single normal cell line. All analogues (9?12) showed diverse antiproliferative effects against all tested human malignant cell lines, but were devoid of any significant cytotoxicity towards the normal foetal lung fibroblasts (MRC-5). A structure?activity relationship study reveals that the introduction of tetrahydrofuran ring, the replacement of C-8 methylene group in the side chain of muricatacin analogues with the O-8 ether functionality, as well as the length of side chain may be beneficial for the antiproliferative effects of these lactones. All novel analogues were more potent than lead compound, (?)-muricatacin, against HL-60 cell line.