Me. Marmion et al., SYNTHESIS AND CHARACTERIZATION OF NOVEL N3O3-SCHIFF BASE COMPLEXES OFTC-99G, AND IN-VIVO IMAGING STUDIES WITH ANALOGOUS TC-99M COMPLEXES, Nuclear medicine and biology, 23(5), 1996, pp. 567-584
Sixteen novel derivatives of 1,1,1-tris (salicylaldiminomethyl)ethane
have been synthesized for the purpose of encapsulating Tc-99m(IV) ions
and generating new Tc-99m radiopharmaceuticals. Two methods for the p
reparation of the Tc-99g(IV) analog complexes are presented; one utili
zes SnCl2 reduction on (TcO4-)-Tc-99g and the other a direct substitut
ion route starting with [(TcCl6)-Tc-99g](2-). Free ligands (H(3)L) are
characterized by melting points, H-1 NMR, C-13 NMR, mass spectroscopy
, TLC, and/or elemental analyses. [(99g)TcL](+) complexes are characte
rized by FAB-ms, UV-VIS, IR and/or CV. An X-ray structural analysis wa
s performed on a crystal of iyl]bis(nitrilomethylidyne)]-bis-3-methoxy
phenol)] tetraphenylborate, where M represents a 1/3 isomorphous mixtu
re of Tc-99g/Sn as determined by SEM. The metal coordination site is 6
-coordinate, composed of N3O3 donor atoms, and intermediate between oc
tahedral and trigonal prismatic geometry. The [(99m)TcL](+) complexes
were prepared in a stannous environment; equivalence of the Tc-99m and
Tc-99g complexes is demonstrated by HPLC techniques. The [SnL](+) com
plex was prepared for comparison purposes. An unusual ligand oxidation
occurs for one series of ligands in which in situ amine --> imine con
version is observed during the complexation reaction in reducing media
. Guinea pig, rat, dog, and human metabolism studies are reported for
selected [(99m)TcL](+) complexes, the myocardial uptake of which appro
aches 2% of the injected dose.