Multigram Synthesis of Trioxanes Enabled by a Supercritical CO<sub>2</sub> Integrated Flow Process
作者:Lingqiao Wu、Bruna L. Abreu、Alexander J. Blake、Laurence J. Taylor、William Lewis、Stephen P. Argent、Martyn Poliakoff、Hamza Boufroura、Michael W. George
DOI:10.1021/acs.oprd.1c00111
日期:2021.8.20
continuous approach using a custom-built high-pressure sapphire photoreactor to synthesize trioxanes via the dearomatization of para-substituted phenols by photogenerated singlet oxygen in supercriticalCO2. CO2 also facilitates mixing with O2 and has lower viscosity, thereby improving penetration into the pores of the solid acid catalyst used for the formation of trioxanes. We show the capabilities
高活性氢过氧化物的光化学合成及其转化为有用的产品,如 1,2,4-三恶烷,在合成有机化学和药物制造中具有广泛的兴趣,特别是因为它们与潜在的抗疟疾和抗癌治疗药物相关,例如,青蒿素。一类抗疟药物基于 1,2,4-三恶烷支架,但由于它们在可氧化溶剂中的不稳定性,以克规模生产此类化合物具有挑战性。此外,目前的方法使用固体氧化剂,这使得连续加工成为问题,或者使用分子氧,需要长达 48 小时的长反应时间。在这里,我们报告了一种新的多克连续方法,使用定制的高压蓝宝石光反应器通过脱芳构化合成三恶烷光生单线态氧在超临界 CO 2 中对位取代的苯酚。CO 2还促进与O 2 的混合并且具有较低的粘度,从而提高对用于形成三恶烷的固体酸催化剂的孔的渗透。我们展示了 5.2 mL 反应器将反应放大到 67 g/天的能力。这种合成方法提供了一个平台,可以在流动条件下快速获取高价值化合物,原子效率高、产率高、反应时间短,并且无需分离危险中间体。
An Asymmetric Synthesis of 1,2,4-Trioxane Anticancer Agents via Desymmetrization of Peroxyquinols through a Brønsted Acid Catalysis Cascade
作者:David M. Rubush、Michelle A. Morges、Barbara J. Rose、Douglas H. Thamm、Tomislav Rovis
DOI:10.1021/ja3052427
日期:2012.8.22
The desymmetrization of p-peroxyquinols using a Bronsted acid-catalyzed acetalization/oxa-Michael cascade was achieved in high yields and selectivities for a variety of aliphatic and aryl aldehydes. Mechanistic studies, suggest that the reaction proceeds through a dynamic kinetic resolution of the peroxy hemiacetal intermediate. The resulting 1,2,4-trioxane products were derivatized and show potent cancer cell-growth inhibition.
Telescoped Continuous Flow Synthesis of 2-Substituted 1,4-Benzoquinones via Oxidative Dearomatisation of para-Substituted Phenols Using Singlet Oxygen in Supercritical CO2
作者:Michael W. George、Bruna L. Abreu、Hamza Boufroura、Jonathan C. Moore、Martyn Poliakoff
DOI:10.1055/s-0041-1737413
日期:2022.8
This paper describes a continuous multi-step synthesis in supercritical CO2. A continuous flow synthesis of 2-substituted 1,4-benzoquinones is reported, and details of the high-pressure reactors are given. This proceeds via the telescoped dearomatisation of p-substituted phenols usingsingletoxygen in supercritical CO2 and an acid-mediated C–C migration. The process has a short residence time of 30
本文描述了在超临界 CO 2中的连续多步合成。报道了2-取代的1,4-苯醌的连续流动合成,并给出了高压反应器的详细信息。这通过在超临界 CO 2中使用单线态氧和酸介导的 C-C 迁移对p取代的苯酚进行伸缩脱芳构化。该工艺的停留时间很短,仅为 30 分钟,总产率和预计产率分别高达 83% 和 9 克/天。该方法能够从光生单线态氧中安全有效地合成 2-取代的 1,4-苯醌,以及廉价且易于获得的p-取代的酚类。该程序具有高原子效率、低光催化剂负载,并用具有潜在危险和腐蚀性的试剂和溶剂替代分子氧、CO 2和危害较小的固体负载酸 Amberlyst-15。