Premium
Synthesis of 77 Br‐labelled 2‐(4‐bromo‐2,5‐dimethoxyphenyl)‐isopropylamine with high specific activity
Author(s) -
Coenen H. H.
Publication year - 1981
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580180516
Subject(s) - chemistry , isopropylamine , trifluoroacetic acid , bromide , trifluoroacetic anhydride , labelling , yield (engineering) , pentane , specific activity , bromine , solvent , chromatography , high performance liquid chromatography , in vivo , medicinal chemistry , radiochemistry , organic chemistry , biochemistry , materials science , metallurgy , enzyme , microbiology and biotechnology , biology
The tagging of 2,5‐dimethoxyphenylisopropylamine (DPIA) with bromine‐77 (T 1/2 = 56 hrs) was reinvestigated in order to achieve high specific activities which are necessary for in‐vivo application of this centrally acting drug. A fast one‐pot synthesis was developed using N‐chlorotetrafluorosuccinimide (NCTFS) and practically carrier‐free bromide to introduce radiobromide into the aromatic ring. Trifluoroacetic anhydride (TFA) was applied both as solvent and as a reversible blocking agent of the free amino group. TFA was also shown to suppress chlorinating sidereactions. Rapid separation of 4‐ 77 Br‐2,5‐dimethoxyphenylisopropylamine was achieved by reverse phase high pressure liquid chromatography. The total labelling and separation procedure takes about two hours, and 4‐ 77 Br‐DOB is obtained with an overall radiochemical yield of 25% and a specific activity of <8 Ci/μmole.