Two-step one-pot synthesis of dihydropyrazinones as Xaa-Ser dipeptide isosteres through morpholine acetal rearrangement
作者:Elena Lenci、Riccardo Innocenti、Gloria Menchi、Cristina Faggi、Andrea Trabocchi
DOI:10.1039/c5ob00783f
日期:——
The synthesis of the uncommon dihydropyrazinone ring was accomplished by a two-step one pot process taking advantage of the ring rearrangement of N-acylated morpholine acetal derived from serine under acidic treatment in the presence of 2,6-lutidine. The mechanism involves an N-acyl iminium intermediate resulting from morpholine acetal ring opening, which occurs after a nucleophilic attack of the amino
罕见的二氢吡嗪酮环的合成是通过两步一锅法,利用在2,6-二甲基吡啶存在下在酸性条件下衍生自丝氨酸的N-酰化吗啉缩醛的环重排来完成的。该机制包括一个ñ从吗啉缩醛环开口,其中氨基酸的氮原子与所述羰基缩醛原子的亲核攻击后发生酰基亚胺中间由此而来。对二氢吡嗪酮的X射线衍射分析(可被用作受约束的Xaa-Ser二肽等排物)显示出平面组装和内部侧链相对于环状分子支架的轴向方向。