We recently described the medicinal chemistry of a new series of heteroaryl-4-oxopyridine/7-oxopyrimidines as CB₂ receptor partial agonists, showing that the functionality of these ligands is controlled by the nature of the heteroaryl function condensed with the pyridine ring. We describe herein the design and synthesis of the 7-oxopyrazolo[1,5-a]pyrimidine-6-carboxamides, structural isomers of our previously reported pyrazolo[3,4-b]pyridines. All of the new compounds showed high affinity and selectivity for the CB₂ receptor in the nanomolar range. In 3,5-cyclic adenosine monophosphate (cAMP) assays, the novel series shows stimulatory effects on forskolin-induced cAMP production acting as inverse agonists.

中文翻译：

---

发现7-氧吡唑并[1,5- a ]嘧啶-6-羧酰胺为强效和选择性CB ₂大麻受体反向激动剂

我们最近描述了一系列新的杂芳基-4-氧代吡啶/ 7-氧嘧啶类化合物作为CB ₂受体部分激动剂的药物化学，显示这些配体的功能性受到与吡啶环缩合的杂芳基功能性质的控制。我们在这里描述了7-氧杂吡唑并[1,5- a ]嘧啶-6-羧酰胺的设计和合成，这是我们先前报道的吡唑并[3,4- b ]吡啶的结构异构体。所有新化合物对纳摩尔范围内的CB ₂受体均显示出高亲和力和选择性。在3,5-环一磷酸腺苷（cAMP）分析中，该新系列显示了对毛喉素诱导的cAMP生成的刺激作用，起反向激动剂的作用。