mitochondrial dehydrogenase, whereas release of lactate dehydrogenase from the cytosol to culture medium was a marker of the cell death. Results: The X-ray crystallography studies showed the conformations adopted by the molecules 2a, 7a, 2b and 7b. Compounds 1a and 14a proved cytotoxic against MT-4 cells and different other cell lines derived from human haematological tumors (CC50 < 10 μM). They influenced on