2,9-Disubstituted-N6-(arylcarbamoyl)-8-azaadenines as new selective A3 adenosine receptor antagonists: Synthesis, biochemical and molecular modelling studies
作者:Giuliana Biagi、Anna Maria Bianucci、Alessio Coi、Barbara Costa、Laura Fabbrini、Irene Giorgi、Oreste Livi、Iolanda Micco、Federica Pacchini、Edoardo Santini、Michele Leonardi、Fatena Ahmad Nofal、Oreste LeRoy Salerni、Valerio Scartoni
DOI:10.1016/j.bmc.2005.04.063
日期:2005.8
A number of N-6-(N-arylcarbamoyl)-2-substituted-9-benzyl-8-azaadenines, obtained by a modification of the synthetic scheme used to prepare selective A(1) ligands, by only three or two steps, are described. At first we prepared a series of 2-phenyl-9-benzyl-8-azaadenines having as N-6 substituent a variously substituted N-phenylcarbamoyl group. Some of these derivatives demonstrated good affinity towards the A(3) subtype but low selectivity. Compounds having p-CF3, p-F and p-OCH3, as substituents on the phenylcarbamoyl group were selected as lead compounds for the second part of this study. Without modifying the N-6 substituent, which would assure A(3) affinity, we varied the 9 and 2 positions on these molecules to enhance selectivity. Some compounds having a p-methyl group on the 2-phenyl substituent showed a very good affinity and selectivity for the A(3) subtype, revealing the first class of A(3) adenosine receptor selective antagonists with a bicyclic structure strictly correlated to the adenine nucleus. The molecular modelling work, carried out using the DOCK program, supplied two models which may be useful for a better understanding of the binding modes. Both models highlighted the preferred interacting tautomeric forms of the antagonists for human A(1) and A(3) receptors. (c) 2005 Elsevier Ltd. All rights reserved.