Phosphodiesterase 4 (PDE4) is a key cAMP-metabolizing enzyme involved in the pathogenesis of inflammatory disease, and its pharmacological inhibition has been shown to exert therapeutic efficacy in chronic obstructive pulmonary disease (COPD). Herein, we describe a drug discovery program aiming at the identification of novel classes of potent PDE4 inhibitors suitable for pulmonary administration. Starting from a previous series of benzoic acid esters, we explored the chemical space in the solvent-exposed region of the enzyme catalytic binding pocket. Extensive structural modifications led to the discovery of a number of heterocycloalkyl esters as potent in vitro PDE4 inhibitors. (S*,S**)-18e and (S*,S**)-22e, in particular, exhibited optimal in vitro ADME and pharmacokinetics properties and dose-dependently counteracted acute lung eosinophilia in an experimental animal model. The optimal biological profile as well as the excellent solid-state properties suggest that both compounds have the potential to be effective topical agents for treating respiratory inflammatory diseases.

中文翻译：

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发现和优化作为呼吸道疾病的吸入式PDE4抑制剂的噻唑烷基和吡咯烷基衍生物

磷酸二酯酶4（PDE4）是一种参与炎症性疾病发病机理的关键cAMP代谢酶，其药理学抑制作用已显示出可在慢性阻塞性肺疾病（COPD）中发挥治疗作用。在本文中，我们描述了一种旨在发现适用于肺部给药的新型新型强效PDE4抑制剂的药物开发程序。从先前的苯甲酸酯系列开始，我们探索了酶催化结合口袋中溶剂暴露区域的化学空间。广泛的结构修饰导致发现许多杂环烷基酯作为有效的体外PDE4抑制剂。（S *，S **）- 18e和（S *，特别地，S **）- 22e在实验动物模型中表现出最佳的体外ADME和药代动力学性质，并剂量依赖性地抵消了急性肺嗜酸性粒细胞增多。最佳的生物学特性以及出色的固态特性表明，这两种化合物都有可能成为治疗呼吸道炎性疾病的有效局部药物。