【JACS】T. Cernak：铂催化胺–羧酸还原胺化

化学深耕堂

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长按识别丨直达原文

深耕点评

美国密歇根大学Tim Cernak团队构建了一种基于铂催化胺–羧酸还原胺化的超高通量直接生物学（D2B）筛选体系，将天然产物微量衍生与细胞表型筛选直接衔接。以leelamine为模型天然产物，1536孔微量反应总体成功率达73%，单次仅消耗约0.03 mg天然产物，并由此获得抗增殖活性较母体提高约7倍的代表性类似物。

深耕亮点：

1）胺–羧酸直接还原胺化构建仲胺。区别于常规胺–羧酸酰胺化，该反应在Karstedt铂催化剂、DavePhos和苯硅烷体系下直接将羧酸还原并与胺偶联形成仲胺，无需预先将羧酸转化为醛。反应兼容多类脂肪族、苄基和芳香羧酸，并可在微量体系中稳定执行，为后续超高通量合成奠定反应基础。

2）1536孔超高通量合成直接进入细胞筛选。4种胺骨架与320种羧酸组合开展1280个微量反应，其中930个检测到预期产物；未经逐一分离纯化的反应液直接用于LNCaP前列腺癌细胞表型筛选，再通过制备级重合成和IC₅₀测定验证命中化合物，实现从微量合成到构效关系分析的连续流程。

3）Janus策略从两个方向拓展天然产物化学空间。同一胺–羧酸还原胺化既可由含胺天然产物连接不同羧酸，也可由含羧酸天然产物连接不同胺类砌块，通过互换天然产物在反应中的角色扩展可获得的类似物结构，并进一步得到具有细胞活性的衍生物。

4）大规模筛选锁定两类关键构效关系。超过900个有效反应形成的SAR数据显示，3-吲哚基和4-甲氧基苯基取代构成两类主要活性系列，连接链长度和刚性同样显著影响抗增殖活性；代表性化合物38和48的活性较母体leelamine提高约7倍。

5）结构优化重塑细胞作用模式。代表性化合物48仍表现出溶酶体依赖的作用特征，并诱导SREBP相关脂质代谢重编程，但未出现母体leelamine相关的显著溶酶体胆固醇滞留，表明天然产物后期结构修饰在增强活性的同时，也可改变其细胞作用模式。

Abstract

Natural products (NPs) are foundational to drug discovery, owing to their diverse molecular scaffolds and novel bioactivities. However, optimizing NPs for optimal bioactivity and improved drug properties is hindered by material scarcity and labor-intensive purification processes. Here, we present an automated ultrahigh-throughput experimentation (ultraHTE) and direct-to-biology (D2B) platform that enables rapid structure–activity relationship (SAR) mapping from miniaturized libraries of synthetic NP analogues, unlocking NPs as a viable starting point for late-stage diversification in drug-lead optimization. Starting from leelamine, a conifer resin-derived tricyclic diterpene with prostate cancer antiproliferative activity, we synthesized leelamine analogues in a 1536-well format, achieving a 73% success rate while consuming only 0.03 mg of NP per reaction. Key to success was the development of a platinum-catalyzed amine–acid reductive amination reaction, which performed well on both amine and complementary acid-derived NPs, in a so-called Janus strategy which more than doubled the accessible chemical space. Direct phenotypic screening in LNCaP cells enabled rapid identification of potent, cell-permeable analogues with robust quality control achieved through iterative resynthesis on preparative scale. SAR insights revealed two key substitution patterns driving potency based on 4-methoxyphenyl and 3-indolyl derivatives. Mechanistic studies─including androgen receptor binding, chemoproteomics, and a lysosomal cholesterol colocalization assay─demonstrated distinct modes of action for optimized analogues compared to leelamine. Collectively, this amine–acid amination-based D2B platform showcases accelerated SAR elucidation from minimal material and cellular profiling, unlocking a framework for mechanism-driven lead discovery in NP chemical space.

作者信息

【个人主页】

https://lsa.umich.edu/chem/

people/faculty/tcernak.html