10 research outputs found
Multicomponent Assembly of Diverse Pyrazin-2(1<i>H</i>)‑one Chemotypes
An expedient and
concise Ugi-based approach for the rapid assembly
of pyrazin-2(1<i>H</i>)-one-based frameworks has been developed.
This convergent approach encompasses skeletal, functional and stereochemical
diversity, exhibiting an unusually high bond-forming efficiency as
well as high structure and step economies. The method involves the
use of readily available commercial reagents and is an example of
the reconciliation of structural complexity with operational simplicity
in a time- and cost-effective manner
Multicomponent Assembly of Diverse Pyrazin-2(1<i>H</i>)‑one Chemotypes
An expedient and
concise Ugi-based approach for the rapid assembly
of pyrazin-2(1<i>H</i>)-one-based frameworks has been developed.
This convergent approach encompasses skeletal, functional and stereochemical
diversity, exhibiting an unusually high bond-forming efficiency as
well as high structure and step economies. The method involves the
use of readily available commercial reagents and is an example of
the reconciliation of structural complexity with operational simplicity
in a time- and cost-effective manner
Copper-Catalyzed Huisgen 1,3-Dipolar Cycloaddition under Oxidative Conditions: Polymer-Assisted Assembly of 4‑Acyl-1-Substituted-1,2,3-Triazoles
We
herein document the first example of a reliable copper-catalyzed Huisgen
1,3-dipolar cycloaddition under oxidative conditions. The
combined use of two polymer-supported reagents (polystyrene-1,5,7-triazabicyclo[4,4,0]dec-5-ene/Cu
and polystyrene-2-iodoxybenzamide) overcomes the thermodynamic
instability of copper(I) species toward oxidation, enabling the reliable
Cu-catalyzed Huisgen
1,3-dipolar cycloadditions in the presence of an oxidant agent. This
polymer-assisted pathway, not feasible under conventional homogeneous
conditions, provides a direct assembly of 4-acyl-1-substituted-1,2,3-triazoles,
contributing to expand the reliability and scope of Cu(I)-catalyzed
alkyne–azide
cycloaddition
Three-Component Assembly of Structurally Diverse 2‑Aminopyrimidine-5-carbonitriles
An
expedient route for the synthesis of libraries of diversely
decorated 2-aminopyrimidine-5-carbonitriles is reported. This approach
is based on a three-component reaction followed by spontaneous aromatization
Enantiospecific Recognition at the A<sub>2B</sub> Adenosine Receptor by Alkyl 2‑Cyanoimino-4-substituted-6-methyl-1,2,3,4-tetrahydropyrimidine-5-carboxylates
A novel
family of structurally simple, potent, and selective nonxanthine
A<sub>2B</sub>AR ligands was identified, and its antagonistic behavior
confirmed through functional experiments. The reported alkyl 2-cyanoimino-4-substituted-6-methyl-1,2,3,4-tetrahy-dropyrimidine-5-carboxylates
(<b>16</b>) were designed by bioisosteric replacement of the
carbonyl group at position 2 in a series of 3,4-dihydropyrimidin-2-ones.
The scaffold (<b>16</b>) documented herein contains a chiral
center at the heterocycle. Accordingly, the most attractive ligand
of the series [(±)<b>16b</b>, <i>K</i><sub>i</sub> <b>=</b> 24.3 nM] was resolved into its two enantiomers by
chiral HPLC, and the absolute configuration was established by circular
dichroism. The biological evaluation of both enantiomers demonstrated
enantiospecific recognition at A<sub>2B</sub>AR, with the (<i>S</i>)-<b>16b</b> enantiomer retaining all the affinity
(<i>K</i><sub>i</sub> <b>=</b> 15.1 nM), as predicted
earlier by molecular modeling. This constitutes the first example
of enantiospecific recognition at the A<sub>2B</sub> adenosine receptor
and opens new possibilities in ligand design for this receptor
Discovery of Potent and Highly Selective A<sub>2B</sub> Adenosine Receptor Antagonist Chemotypes
Three novel families of A<sub>2B</sub> adenosine receptor antagonists
were identified in the context of the structural exploration of the
3,4-dihydropyrimidin-2(1<i>H</i>)-one chemotype. The most
appealing series contain imidazole, 1,2,4-triazole, or benzimidazole
rings fused to the 2,3-positions of the parent diazinone core. The
optimization process enabled identification of a highly potent (3.49
nM) A<sub>2B</sub> ligand that exhibits complete selectivity toward
A<sub>1</sub>, A<sub>2A</sub>, and A<sub>3</sub> receptors. The results
of functional cAMP experiments confirmed the antagonistic behavior
of representative ligands. The main SAR trends identified within the
series were substantiated by a molecular modeling study based on a
receptor-driven docking model constructed on the basis of the crystal
structure of the human A<sub>2A</sub> receptor
Discovery of Potent and Highly Selective A<sub>2B</sub> Adenosine Receptor Antagonist Chemotypes
Three novel families of A<sub>2B</sub> adenosine receptor antagonists
were identified in the context of the structural exploration of the
3,4-dihydropyrimidin-2(1<i>H</i>)-one chemotype. The most
appealing series contain imidazole, 1,2,4-triazole, or benzimidazole
rings fused to the 2,3-positions of the parent diazinone core. The
optimization process enabled identification of a highly potent (3.49
nM) A<sub>2B</sub> ligand that exhibits complete selectivity toward
A<sub>1</sub>, A<sub>2A</sub>, and A<sub>3</sub> receptors. The results
of functional cAMP experiments confirmed the antagonistic behavior
of representative ligands. The main SAR trends identified within the
series were substantiated by a molecular modeling study based on a
receptor-driven docking model constructed on the basis of the crystal
structure of the human A<sub>2A</sub> receptor
Effect of Nitrogen Atom Substitution in A<sub>3</sub> Adenosine Receptor Binding: <i>N</i>‑(4,6-Diarylpyridin-2-yl)acetamides as Potent and Selective Antagonists
We
report the first family of 2-acetamidopyridines as potent and
selective A<sub>3</sub> adenosine receptor (AR) antagonists. The computer-assisted
design was focused on the bioisosteric replacement of the N1 atom
by a CH group in a previous series of diarylpyrimidines. Some of the
generated 2-acetamidopyridines elicit an antagonistic effect with
excellent affinity (<i>K</i><sub>i</sub> < 10 nM) and
outstanding selectivity profiles, providing an alternative and simpler
chemical scaffold to the parent series of diarylpyrimidines. In addition,
using molecular dynamics and free energy perturbation simulations,
we elucidate the effect of the second nitrogen of the parent diarylpyrimidines,
which is revealed as a stabilizer of a water network in the binding
site. The discovery of 2,6-diaryl-2-acetamidopyridines represents
a step forward in the search of chemically simple, potent, and selective
antagonists for the hA<sub>3</sub>AR, and exemplifies the benefits
of a joint theoretical–experimental approach to identify novel
hA<sub>3</sub>AR antagonists through succinct and efficient synthetic
methodologies
Discovery of 3,4-Dihydropyrimidin-2(1<i>H</i>)‑ones As a Novel Class of Potent and Selective A<sub>2B</sub> Adenosine Receptor Antagonists
We
describe the discovery and optimization of 3,4-dihydropyrimidin-2(1<i>H</i>)-ones as a novel family of (nonxanthine) A<sub>2B</sub> receptor antagonists that exhibit an unusually high selectivity
profile. The Biginelli-based hit optimization process enabled a thoughtful
exploration of the structure–activity and structure–selectivity
relationships for this chemotype, enabling the identification of ligands
that combine structural simplicity with excellent hA<sub>2B</sub> AdoR
affinity and remarkable selectivity profiles
Effect of Nitrogen Atom Substitution in A<sub>3</sub> Adenosine Receptor Binding: <i>N</i>‑(4,6-Diarylpyridin-2-yl)acetamides as Potent and Selective Antagonists
We
report the first family of 2-acetamidopyridines as potent and
selective A<sub>3</sub> adenosine receptor (AR) antagonists. The computer-assisted
design was focused on the bioisosteric replacement of the N1 atom
by a CH group in a previous series of diarylpyrimidines. Some of the
generated 2-acetamidopyridines elicit an antagonistic effect with
excellent affinity (<i>K</i><sub>i</sub> < 10 nM) and
outstanding selectivity profiles, providing an alternative and simpler
chemical scaffold to the parent series of diarylpyrimidines. In addition,
using molecular dynamics and free energy perturbation simulations,
we elucidate the effect of the second nitrogen of the parent diarylpyrimidines,
which is revealed as a stabilizer of a water network in the binding
site. The discovery of 2,6-diaryl-2-acetamidopyridines represents
a step forward in the search of chemically simple, potent, and selective
antagonists for the hA<sub>3</sub>AR, and exemplifies the benefits
of a joint theoretical–experimental approach to identify novel
hA<sub>3</sub>AR antagonists through succinct and efficient synthetic
methodologies