may be used as known in the art for example see reshef et al journal of nuclear medicine 49 9 1520 1528 2008 and panwar et al cancer biology amp therapy 4 8 854 860 2005 according to some embodiments of the invention common complexants of radioisotopes like y ir lu dota 1 2 7 10 tetra azacyclododecane n n u2032 n u2033 n u2033 u2033 tetra acetic acid can be attached to compound iii with the aid of an amine terminated linker e g see panwar et al some examples will now be described to further illustrate the invention and to demonstrate how embodiments of the invention may be carried out in practice methyl di tert butyl malonate 18 g 78 16 mmol was dissolved under an argon atmosphere in 600 ml dmf and cooled to 0 u00b0 c khmds 157 ml 0 5m in toluene was added to this solution dropwise the reaction mixture was allowed to reach room temperature and was stirred further for 2 hours 1 5 bis p tolylsulfonato pentane 1 97 g 235 mmol 3 eq was separately dissolved under an argon atmosphere in 100 ml dry dmf at room temperature the khmds deprotonated malonate solution was added drop wise over a period of 3 hours to the ditosylate solution after completion the reaction mixture was stirred for 72 hrs at rt under inert atmosphere the mixture was diluted with water 250 ml extracted with diethyl ether 3 u00d7 50 ml and the combined organic phases were washed with brine dried over a mgso 4 filter and evaporated under reduced pressure the oily residue was taken up in.