A practical access to four new halogen-substituted pyrrole building blocks was realized in two to five synthetic steps from commercially available starting materials. The target compounds were prepared on a 50 mg to 1 g scale, and their conversion to nanomolar inhibitors of bacterial DNA gyrase B was demonstrated for three of the prepared building blocks to showcase the usefulness of such chemical motifs in medicinal chemistry.

No abstract

Naturally occurring styryl lactone, crassalactone D (1), unnatural 4-epi-crassalactone D (2), and the corresponding 7-epimers (3 and 4) have been synthesized starting from d-glucose. The key step of the synthesis is a new one-pot sequence that commenced with a Z-selective Wittig olefination of suitably functionalized sugar lactols with a stabilized ylide, (methoxycarbonylmethylene)-triphenylphosphorane, in dry methanol, to afford 1 or 3, in the mixtures with the corresponding 4-epimers (2 or 4, respectively). A number of 6-O-cinnamoyl derivatives of styryl lactones 1-4 have been prepared, bearing electron donating or electron withdrawing functionalities in the C-4 position of cinnamic acid residue. The synthesized products were evaluated for their in vitro antiproliferative activity against selected human tumour cell lines, whereupon very potent cytotoxicities have been recorded in many cases. SAR analysis indicated some important structural features responsible for biological activity, such as stereochemistry at the C-4 and C-7 positions, as well as the nature of a substituent at the C-4 position in the aromatic ring of cinnamoate moiety. Flow cytometry and Western blot analysis data gave insight in the mechanism underlying antiproliferative effects of the synthesized compounds.

No abstract

A series of new antitumour lactones containing the [3.3.0] bicyclic furano-lactone core and the halogen or azido group at the C-7 position have been designed, synthesized, and evaluated for their in vitro antitumour activity against a panel of human tumour cell lines. Some of the analogues displayed powerful antiproliferative effects to certain human tumour cells, but all of them were devoid of any cytotoxicity towards the normal foetal lung fibroblasts (MRC-5). A SAR study reveals the structural features of these lactones that may affect their antiproliferative activity. These are: the nature of substituent present at the C-7 position, stereochemistry at the C-7 position, the absence of phenyl group at the C-7 position. Flow cytometry data indicate that the cytotoxic effects of the synthesized analogues in a culture of K562 cells are mediated by apoptosis, additionally revealing that these molecules induced changes in cell cycle distribution of these cells. Results of Western blot analysis suggested that the most of synthesized compounds induce apoptosis in K562 cells in caspase-dependent way.