Synthesis of (R,S)-isoproterenol, an inhibitor of tau aggregation, as an 11C-labeled PET tracer via reductive alkylation of (R,S)-norepinephrine with [2-11C]acetone.
Bioorg Med Chem Lett
; 29(16): 2107-2111, 2019 08 15.
Article
em En
| MEDLINE
| ID: mdl-31311732
ABSTRACT
(R,S)-Isoproterenol inhibits the formation of toxic granular tau oligomers associated with neuronal loss and development of cognitive disorders, and is an attractive drug candidate for Alzheimer's disease. To elucidate its behavior in the brain by positron emission tomography, we synthesize (R,S)-[11C]isoproterenol by reductive alkylation of (R,S)-norepinephrine with [2-11C]acetone, which was in turn synthesized in situ under improved conditions afforded a decay-corrected radiochemical yield of 54%. The reductive alkylation using NaBH(OAc)3 as reducing agent in the presence of benzoic acid in DMSO/DMF (6040 v/v) at 100⯰C for 10â¯min gave (R,S)-[11C]isoproterenol in an 87% radio-high performance liquid chromatography (HPLC) analytical yield. HPLC separation using a strong cation exchange column, followed by pharmaceutical formulation in the presence of d/l-tartaric acid, afforded (R,S)-[11C]isoproterenol with a total radioactivity of 2.0⯱â¯0.2â¯GBq, a decay-corrected radiochemical yield of 19⯱â¯2%, chemical and radiochemical purities of 71% and >99%, respectively, and a molar activity of 100⯱â¯13â¯GBq/µmol (nâ¯=â¯3). The overall synthesis time from the end of the bombardment to pharmaceutical formulation was 48â¯min. A preliminary preclinical PET study in a rat demonstrated the potential of the radioligand for the evaluation of the penetration of (R,S)-isoproterenol in human brain.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Acetona
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Norepinefrina
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Compostos Radiofarmacêuticos
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Isoproterenol
Limite:
Animals
Idioma:
En
Revista:
Bioorg Med Chem Lett
Assunto da revista:
BIOQUIMICA
/
QUIMICA
Ano de publicação:
2019
Tipo de documento:
Article