Bejcek Lauren P, Eli Orugbani S, Kapkayeva Diana M, Nafie Jordan, Beutler John A, Gallicchio Emilio, Sackett Dan L, Murelli Ryan P
PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, United States.
Department of Chemistry and Biochemistry, Brooklyn College, The City University of New York, Brooklyn, New York 11210, United States.
J Org Chem. 2025 Jun 6;90(22):7246-7258. doi: 10.1021/acs.joc.5c00284. Epub 2025 May 27.
Colchicine is one of the oldest known microtubule-targeting agents and also represents a classic example of axial chirality and atropisomerism in medicine. This is because colchicine's axially chiral methoxytropone-trimethoxybenzene (called the AC ring) is directly responsible for tubulin binding and is thermodynamically set into the requisite form by a point chiral acetamido group on its B ring. Indeed, desacetamidocolchicine (DAAC), a colchicine analogue without the acetamido group, racemizes within minutes. Herein, we describe the synthesis as well as physical and biological characterization of a series of AC ring-containing molecules that represent B-ring further deconstructed variants of DAAC. These studies revealed a novel analogue with an AC ring that is highly stable to epimerization based not on thermodynamic stabilization but rather a high rotational barrier energy. Profiling and characterization of the dihedral angles were carried out computationally and experimentally using vibrational circular dichroism, demonstrating that the ground state dihedral angles of the new molecules differ significantly from those of colchicine. However, despite this difference, the molecule retained antiproliferative, tubulin-binding, and tubulin polymerization inhibitory activity.
秋水仙碱是已知最古老的微管靶向剂之一,也是医学中轴手性和阻转异构现象的经典例子。这是因为秋水仙碱的轴手性甲氧基色酮 - 三甲氧基苯(称为AC环)直接负责与微管蛋白结合,并且通过其B环上的点手性乙酰氨基在热力学上设定为所需形式。事实上,去乙酰氨基秋水仙碱(DAAC),一种没有乙酰氨基的秋水仙碱类似物,在几分钟内就会发生外消旋化。在此,我们描述了一系列含AC环分子的合成以及物理和生物学特性,这些分子代表了DAAC的B环进一步解构的变体。这些研究揭示了一种具有AC环的新型类似物,该AC环对差向异构化具有高度稳定性,其基础不是热力学稳定,而是高旋转势垒能量。使用振动圆二色性通过计算和实验对二面角进行了分析和表征,表明新分子的基态二面角与秋水仙碱的基态二面角有显著差异。然而,尽管存在这种差异,该分子仍保留了抗增殖、微管蛋白结合和微管蛋白聚合抑制活性。