Rhodium complexes of two bidentate secondary amine oxime ligands and application to the labelling of proteins
作者:G.Ergun Efe、M.R.A. Pillai、E.O. Schlemper、D.E. Troutner
DOI:10.1016/s0277-5387(00)83772-9
日期:1991.1
The syntheses of a new, bifunctional ligand, 3-[N-(4-aminobenzyl)]amino-3-methyl-2-butanone oxime, ligand I, and a non-bifunctional analogue 3-benzylamino-3-methyl-2-butanone oxime, ligand II, the former for labelling proteins with Rh-105 complexes for internal radiotherapy applications are reported. The rhodium complex of ligand II was isolated and characterized by H-1 NMR, IR spectroscopy and X-ray crystallography. The crystal structure consists of discrete mononuclear, neutral and slightly distorted octahedral molecules. The octahedron around rhodium consists of two trans-chlorine atoms and four nitrogen atoms from the two bidentate amine oxime ligands. The complex formed in situ with the bifunctional ligand I gives up to 95% yield with Rh-105 in pH 9 bicarbonate buffer. This complex was converted to the isothiocyanate derivative with thiophosgene and extracted into CHCl3 (91%). Conjugation yields of greater than 90% could be obtained with human gamma-globulin. The protein conjugation method described is suitable for the preparation of Rh-105 labelled antibodies with specific activities of 1.6-9.3 mCi mg-1.