A new method for the synthesis of homoschizokinen 1 and schizokinen 2 is described. 2-tert-Butyl-1,3-di-N-hydroxysuccinimidyl citrate has been applied as the key substrate. The method excludes the possibility of imide formation. The imide of compound 1 has been obtained analogously from the active ester of the 1,3-dioxolan-4-one derivative 5. It has been stated that 13C-n.m.r. signals of the C-3 carbon atoms enable the detection of traces of homoschizokinen 17.