Acid-catalysed epimerization of indolo[2,3-a]quinolizidine derivatives: Role of the nitrogen lone pairs in the mechanism
作者:Mauri Lounasmaa、Mathias Berner、Martin Brunner、Harri Suomalainen、Arto Tolvanen
DOI:10.1016/s0040-4020(98)00614-0
日期:1998.8
The role of the nitrogen lone pairs in the mechanism of the acid-catalysed epimerization of indolo[2,3-a]quinolizidines is investigated using lactams as model compounds. Deethyleburnamonine (3) did not epimerize with trifluoroacetic acid (TFA), whereas deethyldihydroeburnamenine (7) underwent epimerization smoothly. Under treatment with TFA, lactams 12 and 13 both epimerized with ease to a mixture
使用内酰胺作为模型化合物,研究了氮孤对在吲哚并[2,3- a ]喹啉联苯胺的酸催化差向异构化机理中的作用。脱乙基氨磺胺碱(3)没有与三氟乙酸(TFA )发生差向异构化,而脱乙基二氢氨苯甲氨酸(7)顺利进行了差向异构化。在用TFA处理下,内酰胺12和13均容易地差向异构为内酰胺12和13的混合物。当重复使用内酰胺18和19进行实验时,达到了类似的平衡。中级20被内酰胺12的酸催化差向异构化过程捕获(锌还原),可以得出有关该机理的结论。