materials the l isomers or d isomers in the 4 u2032 position of the compounds of the invention can be made all such enantiomeric products are embodied by the compounds of the invention the methods described above can be used to make the compounds according to formula i xxiv table 2 below lists some representative compounds of formula i xxiv in table 2 a straight bond represented by u2014 means that only one anomer is present unless identified as u03b1 or u03b2 the anomeric configuration is unknown a wavy bond represented by means that the compound was isolated as a mixture of the two anomers the antitumor activities of the compounds of the invention were evaluated by a cellular proliferation assay the mtt 3 4 5 dimethylthiazol 2 yl 2 5 diphenyltetrazolium bromide cell proliferation assay first described by mosmann mosmann t u201c rapid colorimetric assay for cellular growth and survival application to proliferation and cytotoxicity assays u201d j immunol methods 1983 dec 16 65 1 2 55 63 and incorporated by reference in its entirety is based on the ability of active mitochondrial reductase enzymes from viable cells to cleave the tetrazolium rings of the pale yellow mtt the cleavage reaction form a purple formazan crystals which is largely impermeable to cell membranes resulting in its accumulation within healthy cells solubilisation of the cells by.