Synthesis of New Diketopiperazines, Thiolation to Thiodiketopiperazines, and Examination of Their ROS-Generating Properties
作者:Sabilla Zhong、Angela E. E. Wandler、Ute Schepers、Martin Nieger、Stefan Bräse
DOI:10.1002/ejoc.201500900
日期:2015.11
A variety of new symmetrical and unsymmetrical diketopiperazines have been prepared from free amino acids by using a previously developed microwave-assisted protocol. This included the successful incorporation of L-pyroglutamic acid as an unusual building block. The diketopiperazines were then thiolated electrophilically to the corresponding bis(methylthio)- and epidithiodiketopiperazines. Initial
通过使用先前开发的微波辅助方案,从游离氨基酸制备了各种新的对称和不对称二酮哌嗪。这包括成功地将 L-焦谷氨酸作为一种不寻常的构建块。然后将二酮哌嗪通过亲电巯基化为相应的双(甲硫基)-和桥二硫二酮哌嗪。最初的实验显示了在 HeLa 细胞中产生活性氧的有希望的活性。
Thiolation of symmetrical and unsymmetrical diketopiperazines
作者:Bettina M. Ruff、Sabilla Zhong、Martin Nieger、Stefan Bräse
DOI:10.1039/c2ob06663g
日期:——
The introduction of sulfur units into a variety of symmetrical and unsymmetrical diketopiperazines (DKPs) is described. We investigated different thiolation methods utilizing several bases and electrophilic sulfur reagents, leading to monomethylthio-, bis(methylthio)-, and epithio-DKPs. Their formation proceeded diastereoselectively, facilitating the application in total syntheses of many thiodiketopiperazine (TDKP) natural products. Furthermore, possible side reactions as well as mechanistic studies and stereochemical structural assignments of the obtained products are given.
Microwave-Assisted Stereoselective One-Pot Synthesis of Symmetrical and Unsymmetrical 2,5-Diketopiperazines from Unprotected Amino Acids
作者:Manuel Jainta、Martin Nieger、Stefan Bräse
DOI:10.1002/ejoc.200800605
日期:2008.11
The facile condensation of unprotected aminoacids by a phosphite-promoted one-step coupling reaction is a highly efficient synthesis to generate stereoselective and optically pure symmetrical and unsymmetrical functionalized diketopiperazines. The use of microwaves enhanced by small amounts of ionic liquid is accompanied by significant improvement in reaction times and yields. Simple filtration through