Synthesis of Aminopyrazoles from Isoxazoles: Comparison of Preparative Methods by in situ NMR Analysis
作者:David Mitchell、Neil Kallman、Kevin Cole、Thomas Koenig、Jonas Buser、Adam McFarland、LuAnne McNulty
DOI:10.1055/s-0035-1561861
日期:——
acetic acid and hydrazine to form the aminopyrazole. A single-step method and a two-step method for the synthesis of aminopyrazoles from isoxazoles are presented and compared. Based on in situ NMR monitoring, both processes proceed through a ketonitrile. In the single-step process, hydrazine serves to both open the isoxazole to the unisolated ketonitrile intermediate and form the aminopyrazole. The two-step
摘要 提出并比较了由异恶唑合成氨基吡唑的一步法和两步法。基于原位NMR监测,这两个过程均通过酮腈进行。在一步法中,肼用于将异恶唑与未分离的酮腈中间体开放,并形成氨基吡唑。该两步法涉及通过用氢氧化物使质子脱氢以生成乙腈,然后加入乙酸和肼以形成氨基吡唑,从而使异恶唑开环。 提出并比较了由异恶唑合成氨基吡唑的一步法和两步法。基于原位NMR监测,这两个过程均通过酮腈进行。在一步法中,肼用于将异恶唑与未分离的酮腈中间体开放,并形成氨基吡唑。该两步法涉及通过用氢氧化物使质子脱氢以生成乙腈,然后加入乙酸和肼以形成氨基吡唑,从而使异恶唑开环。