Iodopyridine-for-iodobenzene substitution for use with low molecular weight radiopharmaceuticals: application to m-iodobenzylguanidine.

Published

Journal Article

Substituting a pyridine ring for a benzene ring in the acylation agent N-succinimidyl 3-iodobenzoate has resulted in a useful approach for the radiohalogenation of monoclonal antibodies, peptides, and labeled biotin conjugates. It was hypothesized that such a substitution in m-iodobenzylguanidine (MIBG), a radiotracer used in the detection and treatment of neuroendocrine tumors, might result in an analogue with more rapid normal tissue clearance, thereby facilitating its use for tumor therapy. For the preparation of this analogue, 3-guanidinomethyl-5-iodopyridine (GMIP; 9b), the silicon precursor 4 was synthesized starting from 5-bromonicotinic acid. Attempts to convert 4 to 9b under various conditions were not successful. Radioiodinated 9b could be prepared by the iododestannylation of the tin precursor 8 in 65-70% radiochemical yield. A number of in vitro, in vivo, and ex vivo studies showed that pyridine-for-benzene substitution in MIBG yielded a compound that no longer was taken up by the uptake-1 pathway.

Full Text

Duke Authors

Cited Authors

  • Vaidyanathan, G; Zalutsky, MR; DeGrado, TR

Published Date

  • November 1998

Published In

Volume / Issue

  • 9 / 6

Start / End Page

  • 758 - 764

PubMed ID

  • 9815170

Pubmed Central ID

  • 9815170

International Standard Serial Number (ISSN)

  • 1043-1802

Digital Object Identifier (DOI)

  • 10.1021/bc980037x

Language

  • eng

Conference Location

  • United States