Synthesis and Molecular Modelling Studies of New 1,3-Diaryl-5-Oxo-Proline Derivatives as Endothelin Receptor Ligands.

The synthesis of seventeen new 1,3-diaryl-5-oxo-proline derivatives as endothelin receptor (ETR) ligands is described. The structural configuration of the new molecules was determined by analyzing selected signals in proton NMR spectra. In vitro binding assays of the human ET and ET receptors allowed us to identify compound as a selective ETR ligand.

High affinity ligands and potent antagonists for the α1D-adrenergic receptor. Novel 3,8-disubstituted [1]benzothieno[3,2-d]pyrimidine derivatives.

A new series of high affinity ligands and antagonists for the α1D-adrenergic receptor (AR) has been discovered. New molecules present a [1]benzothieno[3,2-d]pyrimidin-2,4(1H,3H)-dione or a [1]benzothieno[3,2-d]pyrimidin-4(3H)-one scaffold and bear a 2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl moiety in the 3-position and various amide substituents in the 8-position. In binding assays at the three human cloned α1A-, α1B-, and α1D-AR subtypes, they showed high affinity values, particularly for the α1D-AR subtype.

Novel 4-phenylpiperidine-2,6-dione derivatives. Ligands for α₁-adrenoceptor subtypes.

A number of new 4-phenylpiperidine-2,6-diones bearing at the 1-position an ω-[4-(substituted phenyl)piperazin-1-yl]alkyl moiety were designed and synthesized as ligands for the α(1)-adrenergic receptor (α(1)-AR) subtypes. Some synthesized compounds, tested in binding assays for the human cloned α(1A)-, α(1B)-, and α(1D)-AR subtypes, displayed affinities in the nanomolar range. Highest affinity values were found in derivatives having a butyl connecting chain between the 4-phenylpiperidine-2,6-dione and the phenylpiperazinyl moieties.

New pyrimido[5,4-b]indoles and [1]benzothieno[3,2-d]pyrimidines: high affinity ligands for the alpha(1)-adrenoceptor subtypes.

A number of new pyrimido[5,4-b]indole and [1]benzothieno[3,2-d]pyrimidine derivatives were synthesized and evaluated for their binding and functional properties at alpha(1)-adrenergic receptor (alpha(1)-AR) subtypes. They behaved as potent alpha(1)-AR antagonists. In binding experiments, some of them (RC24 and RC23) showed very high affinity for the alpha(1D)-AR subtype.

New 1,2,3,9-tetrahydro-4H-carbazol-4-one derivatives: analogues of HEAT as ligands for the alpha1-adrenergic receptor subtypes.

With the aim to develop new ligands able to discriminate among the three subtypes of alpha1-adrenergic receptors (alpha1A-AR, alpha1B-AR, and alpha1D-AR), a series of new 1,2,3,9-tetrahydro-4H-carbazol-4-ones bearing a 3-[[[2-(4-hydroxyphenyl)ethyl]amino]methyl] or a 3-[[4-(2-substitutedphenyl)piperazin-1-yl]methyl] side chain were synthesized. The general structure of the new compounds is reminiscent of HEAT and RN5, two potent alpha1-AR antagonists which show high affinities for all three alpha1-AR subtypes. Some derivatives in which one ring of the tetrahydrocarbazolone system was opened were also prepared.

3-Arylpiperazinylethyl-1H-pyrrolo[2,3-d]pyrimidine-2,4(3H,7H)-dione derivatives as novel, high-affinity and selective alpha(1)-adrenoceptor ligands.

The discovery of a new series of selective and high-affinity alpha(1)-adrenoceptor (alpha(1)-AR) ligands, characterized by a 1H-pyrrolo[2,3-d]-pyrimidine-2,4(3H,7H)-dione system, is described in this paper. Some synthesized compounds, including 20, 22, and 30, displayed affinity in the nanomolar range for alpha(1)-ARs and substantial selectivity with respect to 5-HT(1A) and dopaminergic D(1) and D(2) receptors. Functional assays, performed on selected derivatives, showed antagonistic properties.

Novel (E)-alpha-[(1H-indol-3-yl)methylene]benzeneacetic acids as endothelin receptor ligands.

Endothelin-1 (ET-1), a peptide of 21 amino acid residues, is the most potent vasoconstrictor substance known and now it is understood to be one of a family of three mammalian vasoactive peptides that also includes ET-2 and ET-3. The endothelins (ETs) affect multiple organ systems and seem to be involved in the pathogenesis of many diseases such as hypertension, pulmonary hypertension, atherosclerosis, apoptosis inhibition and angiogenesis. The ETs exert their effects via activation of two distinct G-protein coupled receptor subtypes termed ET(A) and ET(B).

A facile synthesis of new 2-carboxamido-3-carboxythiophene and 4,5,6,7-tetrahydro-2-carboxamido-3-carboxythieno[2,3-c]pyridine derivatives as potential endothelin receptors ligands.

Endothelins (ETs) are the most ubiquitous, highly potent and unusually long-lasting peptidic constrictors of human vessels known. Elevated levels of the plasma concentration of ETs were observed in several diseases such as hypertension, acute myocardial infarction, congestive heart failure, renal failure, pulmonary hypertension, and atherosclerosis. ETs exert their activities via specific seven-transmembrane, G protein-coupled receptors.

Synthesis and binding properties of novel selective 5-HT3 receptor ligands.

This work reports on the synthesis and affinities for the 5-HT(3) versus the 5-HT(4) receptor of new piperazinyl-substituted thienopyrimidine derivatives 20-45 with a view to identify potent and selective ligands for the 5-HT(3) receptor. Some of the new compounds show good affinity for the 5-HT(3) receptor and, notably, do not display any affinity for the 5-HT(4) receptor. 4-(4-Methyl-1-piperazinyl)-2-methylthio-6,7-dihydro-5H-cyclopenta[4,5]thieno[2,3-d]pyrimidine 31 exhibits the highest affinity for the 5-HT(3) receptor (Ki = 33 nM) and behaves as noncompetitive antagonist.

New pyrimido[5,4-b]indoles as ligands for alpha(1)-adrenoceptor subtypes.

A new series of compounds were designed as structural analogues of the alpha(1)-AR ligand RN5 (4), characterized by a tricyclic 5H-pyrimido[5,4-b]indole-(1H,3H)2,4-dione system connected through an alkyl chain to a phenylpiperazine (PP) moiety. These compounds were synthesized and tested in binding assays on human alpha(1A)-AR, alpha(1B)-AR, and alpha(1D)-AR subtypes expressed in HEK293 cells. Several structural modifications were performed on the PP moiety, the tricyclic system, and the connecting alkyl chain.