A facile and novel synthesis of N2-, C6-substituted pyrazolo[3,4-d]pyrimidine-4 carboxylate derivatives as adenosine receptor antagonists
                                
                                    
                                        作者:G. Venkatesan、P. Paira、S.L. Cheong、S. Federico、K.N. Klotz、G. Spalluto、G. Pastorin                                    
                                    
                                        DOI:10.1016/j.ejmech.2015.01.046
                                    
                                    
                                        日期:2015.3
                                    
                                    An efficient synthetic procedure was adopted to synthesize a series of new molecules containing the pyrazolo[3,4-d]pyrimidine (PP) scaffold, which have been evaluated as promising human adenosine receptor (AR) antagonists. The effect of substitutions at the N-2, C-4 and C-6 positions of PPs on the affinity and selectivity towards the adenosine receptors were explored. Most of the pyrazolo[3,4-d]pyrimidine-4-carboxylates displayed from moderate to good affinity at the human A(3)AR (hA(3)AR), as indicated by the low micromolar range of K-i values (K-i hA(3)AR = 0.7-34 mu M). In particular, compounds 60 and 62 displayed good affinity at the hA(3)AR (60, K-i hA(3)AR = 2.2 mu M and 62, K-i hA(3)AR = 2.9 mu M) and selectivity towards the other AR subtypes (60, >46-fold selective and 62, >34-fold selective, respectively). In view of these results, these novel PP analogues were docked both in the crystallographic structure of the hA(2A)AR and in a homology model of the hA(3)AR in order to support the structure activity relationship (SAR) analysis. These preliminary results demonstrated that pyrazolo[3,4-d]pyrimidine can be considered a promising scaffold to obtain new molecules with potent hA(3)AR antagonist activity. (C) 2015 Elsevier Masson SAS. All rights reserved.