Convenient Synthesis of Pyrazolo[4′,3′:5,6]pyrano[4,3-c][1,2]oxazoles via Intramolecular Nitrile Oxide Cycloaddition
作者:Vaida Milišiūnaitė、Elena Plytninkienė、Roberta Bakšienė、Aurimas Bieliauskas、Sonata Krikštolaitytė、Greta Račkauskienė、Eglė Arbačiauskienė、Algirdas Šačkus
DOI:10.3390/molecules26185604
日期:——
A simple and efficient synthetic route to the novel 3a,4-dihydro-3H,7H- and 4H,7H-pyrazolo[4′,3′:5,6]pyrano[4,3-c][1,2]oxazole ring systems from 3-(prop-2-en-1-yloxy)- or 3-(prop-2-yn-1-yloxy)-1H-pyrazole-4-carbaldehyde oximes has been developed by employing the intramolecular nitrile oxide cycloaddition (INOC) reaction as the key step. The configuration of intermediate aldoximes was unambiguously
一种简单高效的新型3a,4-dihydro-3 H ,7 H - 和4 H ,7 H -pyrazolo[4',3':5,6]pyrano[4,3- c ][1]合成路线,2] 恶唑环系统由 3-(prop-2-en-1-yloxy)- 或 3-(prop-2-yn-1-yloxy)-1 H -pyrazole-4-carbaldehyde oximes 开发分子内氧化腈环加成 (INOC) 反应是关键步骤。中间醛肟的构型是使用 NOESY 实验数据和亚胺基部分的1 J CH偶联常数的大小的比较明确确定的,对于主要的合成,这些常数大了大约 13 Hz。异构体。所得杂环产物的结构通过详细的1 H、13 C 和15 N NMR 光谱实验和 HRMS 测量证实。