Synthesis of Spiro-Fused (C5)-Isoxazolino-(C4)-pyrazolones (1-Oxa-2,7,8-triazaspiro[4,4]-2,8-dien-6-ones) via 1,3-Dipolar Cycloaddition and Cycloelimination
作者:Robert E. Sammelson、Chamindra D. Gurusinghe、Jeffrey M. Kurth、Marilyn M. Olmstead、Mark J. Kurth
DOI:10.1021/jo010895d
日期:2002.2.1
also concluded that all condensations/cycloeliminations, except with hydrazine itself, were more effective with catalysts or higher reaction temperatures. For example, TiCl(4) was an efficient catalyst for hydrazone formation and cycloelimination with methylhydrazine, while phenyl-, benzyl-, and (4-methoxyphenyl)hydrazine reacted effectively without catalyst in refluxing xylene.
报道了一种高效且选择性的合成螺旋稠合的(C5)-异恶唑啉基-(C4)-吡唑啉酮(C)的方法。该过程包括利用Baylis-Hillman反应-或更快速,逐步的MAC程序-生成I,然后进行1,3-偶极环加成和Swern氧化,生成β-酮酸酯H,将其与肼衍生物缩合,得到进行了环除。通过光谱分析以及5的单晶X射线证实了这些新颖的螺稠(C5)-异恶唑啉基-(C4)-吡唑啉酮。我们还得出结论,除肼本身外,所有缩合/环消除均更有效。催化剂或更高的反应温度。例如,TiCl(4)是for形成和用甲基肼环化的有效催化剂,而苯基,苄基,