Bioorganic & Medicinal Chemistry Letters 2013-02-15

Synthesis of 2,6-difluoro-N-(3-[11C]methoxy-1H-pyrazolo[3,4-b]pyridine-5-yl)-3-(propylsulfonamidio)benzamide as a new potential PET agent for imaging of B-Raf(V600E) in cancers.

Min Wang, Mingzhang Gao, Kathy D Miller, Qi-Huang Zheng

Index: Bioorg. Med. Chem. Lett. 23(4) , 1017-21, (2013)

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Abstract

The authentic standard 2,6-difluoro-N-(3-methoxy-1H-pyrazolo[3,4-b]pyridine-5-yl)-3-(propylsulfonamidio)benzamide was synthesized from 2,6-difluorobenzoic acid and 3-amino-5-hydroxypyrazole in 9 steps with 1% overall chemical yield. Direct desmethylation of the reference standard with TMSCl/NaI gave the precursor 2,6-difluoro-N-(3-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-yl)-3-(propylsulfonamidio)benzamide for radiolabeling in 70% yield. The target tracer 2,6-difluoro-N-(3-[(11)C]methoxy-1H-pyrazolo[3,4-b]pyridine-5-yl)-3-(propylsulfonamidio)benzamide was prepared from the precursor with [(11)C]CH(3)OTf through O-[(11)C]methylation and isolated by HPLC combined with SPE in 40-50% decay corrected radiochemical yields with 370-740 GBq/μmol specific activity at end of bombardment (EOB).Copyright © 2012 Elsevier Ltd. All rights reserved.