PT  - JOURNAL ARTICLE
AU  - T Ishida
AU  - Y In
AU  - M Shibata
AU  - M Doi
AU  - M Inoue
AU  - I Yanagisawa
TI  - On the structure-activity relationship of histamine H2-receptor antagonists based on the X-ray crystal structures and 1H-NMR spectra of amidine derivatives.
DP  - 1987 Apr 01
TA  - Molecular Pharmacology
PG  - 410--416
VI  - 31
IP  - 4
4099  - http://molpharm.aspetjournals.org/content/31/4/410.short
4100  - http://molpharm.aspetjournals.org/content/31/4/410.full
SO  - Mol Pharmacol1987 Apr 01; 31
AB  - The conformation of six amidine compounds, which possess a common 3-[(4-thiazolyl)methylthio]propionylamidine framework but exhibit different activities as histamine H2-receptor antagonists, have been subjected to both single crystal X-ray structural and 1H-NMR analyses. The X-ray studies suggest a correlation between antagonist activity and the relative spatial orientation of the thiazolyl and amidine nitrogen atoms. This correlation is supported by a comparison of the conformations observed for the amidines with those of other H2-receptor antagonists and reveal that a folded conformation, specifically the NH...N intramolecular hydrogen-bonded configuration, is important for antagonist activity. The 1H-NMR measurements on the active amidine compounds show that the intramolecular NH...N bond is likely to be present in solution.