P-ALKYLATED MACROCYCLIC POLYPHOSPHINES PO LYOXIDES

With the aim of obtaining complexes of gamma-emitters and paramagnetic ions for use as imaging reagents and contrast agents, the synthesis o f ligands was performed by cyclocondensation between dioxophosphids, a lpha,omega-dihalogenoalkanes, and alkenes. These reactions lead to new cyclic P-alkylated polyphosphine polyoxides with saturated and unsatu rated bridges. The 1:1 cyclocondensation products are obtained predomi nantly over the 2:2 and 3:3 cyclocondensation products. The formation of tetraphosphorated cycles becomes significant when it is allowed by the dihalide configuration. The origin of these orientations is discus sed and a mechanism is also presented for these reactions.