Synthesis, ligand-receptor modeling studies and pharmacological evaluation of novel 4-modified-2-aryl-1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives as potent and selective human A3 adenosine receptor antagonists.

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Colotta V, Catarzi D, Varano F, Lenzi O, Filacchioni G, Martini C, Trincavelli L, Ciampi O, Traini C, Pugliese AM, Pedata F, Morizzo E, Moro S

Bioorg Med Chem. 2008 Jun 1;16(11):6086-102. doi: 10.1016/j.bmc.2008.04.039. Epub 2008 Apr 24.

PubMed ID

18468446 [ View in PubMed

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Abstract

The study of some 4-substituted-2-aryl-1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives, designed as hA(3) adenosine receptor antagonists, is reported. The new compounds bear on the four-position different acylamino, sulfonylamino, benzylureido and benzyloxy moieties, which have also been combined with a para-methoxy group on the 2-phenyl ring or with a nitro residue at the six-position. Many derivatives show high hA(3) adenosine receptor affinities and selectivities both versus hA(1) and hA(2A) receptors. The observed structure-affinity relationships of this class of antagonists have been exhaustively rationalized using the recently published ligand-based homology modeling (LBHM) approach. The selected 4-bismethanesulfonylamino-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-1-one (13), which shows high hA(3) affinity (K(i)=5.5nM) and selectivity versus hA(1), hA(2A) (both selectivity ratios>1800) and hA(2B) (cAMP assay, IC(50)>10,000nM) receptors, was tested in an in vitro rat model of cerebral ischemia, proving to be effective in preventing the failure of synaptic activity, induced by oxygen and glucose deprivation in the hippocampus, and in delaying the occurrence of anoxic depolarization.

DrugBank Data that Cites this Article

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Theophylline	Adenosine receptor A1	Ki (nM)	6200	N/A	N/A	Details
Theophylline	Adenosine receptor A2a	Ki (nM)	7900	N/A	N/A	Details