Ghatak Trisha, Shah Chandan, Althagafi Ismail, Giri Nand Gopal, Nath Mahendra, Pratap Ramendra
Department of Chemistry, University of Delhi, Delhi, 110007, India.
Department of Chemistry, Faculty of Science, Umm Al-Qura University, Makkah, 21955, Saudi Arabia.
Org Biomol Chem. 2024 Feb 28;22(9):1859-1870. doi: 10.1039/d3ob01997g.
A facile one-pot cascade synthesis involving simultaneous pyrazole formation followed by iodine/DMSO-mediated oxidation has been established to afford 1-aryl-2-(3-aryl)-1-pyrazol-5-yl-ethane-1,2-diones. Primarily, a two-pot approach has been established which includes the reaction of 3-methylthio-1,5-diaryl-2-pentene-1,5-diones with hydrazine in the first step to afford pyrazole, which was eventually oxidized in the next steps in the presence of iodine in DMSO. Furthermore, we performed both steps in the same pot to afford 1,2-dicarbonyl compounds in good yield. The structure of one of the compounds was confirmed by single crystal X-ray analysis. DMSO served as a solvent as well as an oxidant. Moreover, -substituted hydrazines provided 1-(1-substituted-3-aryl-1-pyrazol-5-yl)-2-arylethane-1,2-diones regioselectively. Furthermore, for synthetic application, 1-aryl-2-(3-aryl)-1-pyrazol-5-yl-ethane-1,2-diones were treated with -phenylenediamine to afford pyrazole-functionalized quinoxaline in good yield. A control reaction was carried out to understand the mechanism of product formation.
已建立一种简便的一锅法串联合成方法，该方法涉及同时形成吡唑，随后进行碘/二甲亚砜介导的氧化反应，以得到1-芳基-2-(3-芳基)-1-吡唑-5-基乙烷-1,2-二酮。首先，已建立了一种两步法，第一步是3-甲硫基-1,5-二芳基-2-戊烯-1,5-二酮与肼反应生成吡唑，最终在接下来的步骤中，在碘存在的二甲亚砜中进行氧化。此外，我们在同一反应釜中进行了这两个步骤，以高收率得到1,2-二羰基化合物。其中一种化合物的结构通过单晶X射线分析得以确证。二甲亚砜既作为溶剂又作为氧化剂。此外，α-取代肼可区域选择性地提供1-(1-取代-3-芳基-1-吡唑-5-基)-2-芳基乙烷-1,2-二酮。此外，为了进行合成应用，将1-芳基-2-(3-芳基)-1-吡唑-5-基乙烷-1,2-二酮与对苯二胺反应，以高收率得到吡唑官能化的喹喔啉。进行了对照反应以了解产物形成的机理。
