Department of Organic Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Bioorg Med Chem. 2011 Aug 15;19(16):5006-11. doi: 10.1016/j.bmc.2011.06.057. Epub 2011 Jun 25.
The single step synthesis of a newly designed series of strigolactones (SLs) from cyclic keto enols is described. The germinating activity of these SL analogues towards seeds of the parasitic weeds Striga and Orobanche spp. is reported. The first of these SL analogues are derived from the hydroxyl γ-pyrones kojic acid and maltol, the second type from hydroxyl α-pyrones, namely, 4-hydroxy-6-methyl-2H-pyran-2-one and 4-hydroxy-coumarin and the third type from 1,3-diketones, namely, 1,3-cyclohexane-dione (dimedone) and tricyclic 1,3-dione. All keto enols are coupled in a single step with the appropriate D-ring precursor in the presence of a base to give the desired SL analogues. All SL analogues are acceptably biologically active in inducing the germination of seeds of Striga hermonthica and Orobanchecernua. Most interesting are the analogues derived from 4-hydroxy coumarin and dimedone, as they have a remarkably high biological activity towards the seeds of parasitic weeds at relatively low concentrations, comparable with that of the general standard stimulant GR24.
从环状酮烯醇出发，经单步反应合成了一系列新设计的独脚金内酯（SLs）。报道了这些 SL 类似物对列当属（Striga）和列当属（Orobanche）寄生杂草种子的萌发活性。其中第一个 SL 类似物来源于羟基γ-吡喃酮（koji acid 和 maltol），第二个来源于羟基α-吡喃酮（4-hydroxy-6-methyl-2H-pyran-2-one 和 4-hydroxy-coumarin），第三个来源于 1,3-二酮（1,3-cyclohexanedione (dimedone) 和三环 1,3-二酮）。所有的酮烯醇在碱的存在下与适当的 D-环前体进行单步偶联，得到所需的 SL 类似物。所有的 SL 类似物都能有效地诱导独脚金属（Striga hermonthica）和列当属（Orobanche cernua）种子的萌发，具有可接受的生物活性。最有趣的是来源于 4-羟基香豆素和二亚甲基酮的类似物，因为它们在相对较低的浓度下对寄生杂草种子具有极高的生物活性，与一般标准刺激剂 GR24 的活性相当。
