Jl. Musachio et al., -(P-TRIMETHYLSILYLPHENYL)TROPANE-2-BETA-CARBOXYLIC ACID METHYL-ESTER - A NEW PRECURSOR FOR THE PREPARATION OF [I-123] RTI-55, Applied radiation and isotopes, 47(1), 1996, pp. 79-81
Citations number
15
Categorie Soggetti
Nuclear Sciences & Tecnology","Radiology,Nuclear Medicine & Medical Imaging
Here we report the synthesis of 3 beta-(p-trimethylsilylphenyl)tropane
-2 beta-carboxylic acid methyl ester, a new, easily prepared precursor
for the synthesis of radioiodinated versions of RTI-55. In contrast t
o the 3 beta-(p-trimethylstannylated) precursor for radioiodination, t
he aryl silane is prepared directly by the 1,4 addition of p-trimethyl
silylphenylmagnesium iodide to anhydroecgonine methyl ester in 49% yie
ld (Scheme 1). Radioiododesilylation proceeded smoothly (approx. 85% r
adioincorporation after 15 min at room temperature) using 1 mu g of th
e novel precursor in trifluoroacetic acid and chloramine-T as oxidant.
Isolated radiochemical yields for I-125 and I-123 radiolabelings were
72 and 48%, respectively, with a calculated specific activity for [I-
123]RTI-55 of >2000 mCi/mu mol.