Dibutylphosphate (DBP) mediated synthesis of cyclic N,N′-disubstituted urea derivatives from amino esters: a comparative study
作者:Sumit K. Agrawal、Manisha Sathe、A.K. Halve、M.P. Kaushik
DOI:10.1016/j.tetlet.2012.08.083
日期:2012.11
The N,N′-disubstituted urea derivatives such as amino acid hydantoins and dihydrouracil derivatives were prepared starting from natural and unnatural amino acid esters using dibutylphosphate (DBP). During the attempted synthesis of N-heterocycles with larger than six-membered rings containing the N,N′-disubstituted urea functionalities, three unexpected products namely squamolone, N-methyl pyrrolidine-2-one
的Ñ,Ñ '二取代的脲衍生物如氨基酸乙内酰脲和二氢尿嘧啶衍生物制备来自使用磷酸二丁酯(DBP)的天然和非天然氨基酸酯起始。在试图合成具有大于六元环的N-杂环的N-杂环的过程中,所述六元环包含N,N′-二取代的尿素官能团,分离了三种意想不到的产物,即扁豆酚酮,N-甲基吡咯烷-2-酮和二酮哌嗪。