Synthesis and labelling of epidepride

YANG Min，

PEI Zhu-Guo，

HU Ming-Yang，

WANG Bo-Cheng，

ZHOU Xing-Qin

Nuclear Science and Techniques

Vol.12, No.2

pp.111-116

Published in print 01 May 2001

CLC：O628.5+1, O629.7, O621.3

28600

S-(-)-N-[(1-ethyl-2-pyrrolidinyl)methyl]-5-iodo-2,3-dimethoxybenzamide (proposed generic name, epidepride) is a very potent dopamine D2 antagonist. It was synthesized by five steps from 3-methoxysalicylic acid. [¹³¹I]epidepride was obtained in 97.3% radiochemical yields from the corresponding 5-(tributyltin) derivative using hydrogen peroxide as the oxidant. The aryltin precursor was prepared from non-labelled epidepride by palladium-catalyzed stannylation using bis(tri-n-butyltin) in triethylamine. [¹³¹I]epidepride was stable under 4°C, and partition coefficient was 72.3 at pH 7.40. The biodistribution study in rats exihibited high localization in the striatum of the brain with the striatum/cerebellum ratio reaching 237/1 at 320 min postinjection. All these results suggest that [¹³¹I]epidepride may be used widely as a useful dopamine D2 receptor imaging agent for SPECT.

[131I]epideprideDopamine D2 antagonistSynthesizeAryltin precursorBiodistributionSPECT

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