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Updated: Aug 12, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
New high affinity H3 receptor agonists without a basic side chain
Ruengwit Kitbunnadaj1, Marcel Hoffmann, Silvina A Fratantoni
1Leiden/Amsterdam Center of Drug Research (LACDR), Division of Medicinal Chemistry, Department of Pharmacochemistry, Faculty of Chemistry, Vrije Universiteit Amsterdam, The Netherlands.
Abstract:
In this study, we replaced the basic amine function of the known histamine H(3) receptor agonists imbutamine or immepip with non-basic alcohol or hydrocarbon moieties. All compounds in this study show a moderate to high affinity for the cloned human H(3) receptor and, unexpectedly, almost all of them act as potent agonists. Moreover, in the alcohol series, we consistently observed an increased selectivity for the human H(3) receptor over the human H(4) receptor, but none of the compounds in this series possess increased affinity and functional activity compared to their alkylamine congeners. In this new series of compounds VUF5657, 5-(1H-imidazol-4-yl)-pentan-1-ol, is the most potent histamine H(3) receptor agonist (pK(i) = 8.0 and pEC(50) = 8.1) with a 320-fold selectivity at the human H(3) receptor over the human H(4) receptor.
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