myeloproliferative neoplasms (MPNs). At present, there is still an obvious unmet medical need for selective JAK2 inhibitors in clinic. In this paper, a class of 2-aminopyridine derivatives as potent and selective JAK2 inhibitors was obtained by combining drug design, synthesis and structure-activity relationship studies based on the previously identified lead Crizotinib. Among them, 21b exhibited high inhibitory activity
                                    JAK2激酶的异常激活与骨髓增生性肿瘤(M
PNs)的发生和发展密切相关。目前,选择性JAK2
抑制剂在临床上仍有明显未满足的医疗需求。本文在先前确定的先导
克唑替尼的基础上,结合药物设计、合成和构效关系研究,获得了一类作为强效选择性JAK2
抑制剂的2-
氨基
吡啶衍生物。其中,21b对JAK2表现出高抑制活性,IC 50为9 nmol/L,而且其选择性分别是JAK1和JAK3的276倍和184倍。此外,21b对HEL细胞具有显着的抗增殖活性,并且还抑制JAK2的
磷酸化及其下游信号通路。这些结果表明 2-
氨基吡啶化合物21b有可能被开发为选择性 JAK2 
抑制剂以供进一步研究。