Dadiboyena Sureshbabu, Valente Edward J, Hamme Ashton T
Department of Chemistry, College of Science, Engineering and Technology, Jackson State University, Jackson, Mississippi 39217 USA.
Tetrahedron Lett. 2009 Jan 21;50(3):291. doi: 10.1016/j.tetlet.2008.10.145.
The syntheses of an important class of hitherto unreported 1,3,5-pyrazoles, inspired by an unanticipated eliminatory ring opening are described. The reported pyrazole compounds were constructed through the Huisgen cyclization of 2-methylene-1,3,3-trimethylindoline and an in situ generated nitrile imine. The newly formed spiro-pyrazoline intermediate presumably then undergoes a ring opening/elimination process to afford a pyrazole, as evidenced by single X-ray crystal data. The current report constitutes the first formal observation of this kind of ring opening involving a spiro-pyrazoline intermediate.
本文描述了一类迄今为止尚未报道的1,3,5-吡唑的合成，该合成受到意外的消除开环反应的启发。所报道的吡唑化合物是通过2-亚甲基-1,3,3-三甲基吲哚啉与原位生成的腈亚胺的惠斯根环化反应构建而成。新形成的螺吡唑啉中间体可能随后经历开环/消除过程以得到吡唑，单晶X射线晶体数据证明了这一点。本报告首次正式观察到这种涉及螺吡唑啉中间体的开环反应。
