Highly Potent, Stable, and Selective Dimeric Hetarylpropylguanidine-Type Histamine H2 Receptor Agonists
On the basis of the long-known prototypic pharmacophore 3-(1H-imidazol-4-yl)propylguanidine (SK&F 91486, 2), monomeric, homodimeric, and heterodimeric bisalkylguanidine-type histamine H2 receptor (H2R) agonists with various alkyl spacers were synthesized. Aiming at increased H2R selectivity of the ligands, the imidazol-4-yl moiety was replaced by imidazol-1-yl, 2-aminothiazol-5-yl or 2-amino-4-methylthiazol-5-yl according to a bioisosteric approach. All compounds turned out to be partial or full agonists at the h/gp/rH2R. The most potent analogue, the thiazole-type heterodimeric ligand 63 (UR-Po461), was a partial agonist (Emax = 88%) and 250 times more potent than histamine (pEC50: 8.56 vs 6.16, gpH2R, atrium). The homodimeric structures 56 (UR-Po395) and 58 (UR-Po448) exhibited the highest hH2R affinities (pKi: 7.47, 7.33) in binding studies. Dimeric amino(methyl)thiazole derivatives, such as 58, generated an increased hH2R selectivity compared to the monomeric analogues, e.g., 139 (UR-Po444). Although monomeric ligands showed up lower affinities and potencies at the H2R, compounds with a short alkylic side chain like 129 (UR-Po194) proved to be highly affine hH4R ligands.
Related content
euroSAMPL1 blind prediction challenge with Chemaxon's Calculators and Predictors
euroSAMPL1 blind prediction challenge - using calculators and predictors by Chemaxon
Predicting pKa
One of the most important physicochemical properties of small molecules and macromolecules are the...
Calculate on the cloud
In order to increase the flexibility, access and integrability, Calculators and Predictors have...
Coupling stabilizers open KV1-type potassium channels
ABSTRACT: The opening and closing of voltage-gated ion channels are regulated by voltage sensors...