名称:
                                The 1,2,4-Triazolo[4,3-a]pyrazin-3-one as a Versatile Scaffold for the Design of Potent Adenosine Human Receptor Antagonists. Structural Investigations to Target the A2A Receptor Subtype
                             
                            
                                摘要:
                                In this work, we describe the identification of the 1,2,4-triazolo[4,3-a]pyrazin-3-one as a new versatile scaffold for the development of adenosine human (h) receptor antagonists. The new chemotype ensued from a molecular simplification approach applied to our previously reported 1,2,4-triazolo[4,3-a]quinoxalin-1-one series. Hence, a set of novel 8-amino-2-aryl-1,2,4-triazolopyrazin-3-one derivatives, featured by different substituents on the 2-phenyl ring (R) and at position 6 (R-6), was synthesized with the main purpose of targeting the hA(2A) adenosine receptor (AR). Several compounds possessed nanomolar affinity for the hA(2A) AR (K-i = 2.910 nM) and some, very interestingly, also showed high selectivity for the target. One selected potent hA(2A) AR antagonist (12, R = H, R-6 = 4-methoxyphenyl) demonstrated some ability to counteract MPP+-induced neurotoxicity in cultured human neuroblastoma SH-SY5Y cells, a widely used in vitro Parkinsons disease model. Docking studies at hAR structures were performed to rationalize the observed affinity data.