Mwakaboko Alinanuswe S, Zwanenburg Binne
Radboud University of Nijmegen Institute for Molecules and Materials Cluster of Organic Chemistry Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands.
European J Org Chem. 2016 Jul;2016(21):3495-3499. doi: 10.1002/ejoc.201600576. Epub 2016 Jun 27.
Strigolactones (SLs) are important new plant hormones that receive much attention in current plant science. SLs are produced by many plants and are exuded by the root system. SLs are, amongst others, germination stimulants for seed of parasitic weeds. Naturally occurring SLs invariably contain three annelated rings, the ABC-scaffold, connected to a butenolide (the D-ring) via an enol ether unit. The synthesis of natural SLs requires many steps, therefore there is a continuous search for SL analogues with a simpler structure but with retention of bioactivity. In this study modified D-ring variants are investigated, especially analogues having a methyl group at C-2 instead of a hydrogen. For these analogues the ABC-scaffolds of GR24 and Nijmegen-1 were used. The coupling reaction proceeds profoundly better with chlorobutenolides than with the corresponding bromides. Bioassays reveal that the introduction an extra methyl at C-2 does not influence the germination activity, which is relevant for gaining insight in the mode of action of SLs.
独脚金内酯（SLs）是当前植物科学领域备受关注的重要新型植物激素。许多植物都会产生SLs，并通过根系分泌。SLs是寄生杂草种子的萌发刺激物之一。天然存在的SLs总是含有三个稠合环，即ABC骨架，通过烯醇醚单元与丁烯内酯（D环）相连。天然SLs的合成需要许多步骤，因此人们一直在不断寻找结构更简单但仍保留生物活性的SL类似物。在本研究中，对修饰的D环变体进行了研究，特别是在C-2位具有甲基而非氢原子的类似物。对于这些类似物，使用了GR24和奈梅亨-1的ABC骨架。与相应的溴化物相比，氯丁烯内酯的偶联反应进行得更好。生物测定表明，在C-2位引入一个额外的甲基不会影响萌发活性，这对于深入了解SLs的作用模式具有重要意义。
