Substituent effects of cis-cinnamic acid analogues as plant growh inhibitors
摘要:
1-O-cis-Cinnamoyl-beta-D-glucopyranose is one of the most potent allelochemicals that has been isolated from Spiraea thunbergii Sieb by Hiradate et al. It derives its strong inhibitory activity from cis-cinnamic acid (cis-CA), which is crucial for phytotoxicity. By preparing and assaying a series of cis-CA analogues, it was previously found that the key features of cis-CA for lettuce root growth inhibition are a phenyl ring, cis-configuration of the alkene moiety, and carboxylic acid. On the basis of a structure-activity relationship study, the substituent effects on the aromatic ring of cis-CA were examined by systematic synthesis and the lettuce root growth inhibition assay of a series of cis-CA analogues having substituents on the aromatic ring. While ortho- and para-substituted analogues exhibited low potency in most cases, meta-substitution was not critical for potency, and analogues having a hydrophobic and sterically small substituent were more likely to be potent. Finally, several cis-CA analogues were found to be more potent root growth inhibitors than cis-CA. (C) 2013 Elsevier Ltd. All rights reserved.
Template-stereocontrolled [2 + 2] photoreactions directed by surface recognition on hydrophilic functionalized carbon materials
作者:Gabriela Ortega、Alexander Briceño
DOI:10.1039/c7ce01090g
日期:——
Supramolecular assistance of the regioselective synthesis of single dimers from [2 + 2] photoreactions surface-directed by multivalent H-bonding exo-templates based on hydrophilic carbon materials (HCMs) is highlighted for the first time. Supramolecular photochemistry of stilbenes assisted by either functionalizedcarbonnanotubes or sub-microspheres afforded a single rtct-isomer after two consecutive
Visible-light promoted oxidative cyclization of cinnamic acid derivatives using xanthone as the photocatalyst
作者:Bin Zhao、Bo Xu
DOI:10.1039/d0ob02417a
日期:——
coumarin derivatives via a tandem double bond isomerization/oxidative cyclization of cinnamic acids. Inexpensive and stable xanthone was used as the photocatalyst, and readily available Selectfluor was used as the oxidant. This method tolerates a wide range of functional groups and offers excellent chemical yields in general. Besides, the photocatalytic oxidative cyclization of cinnamic acid esters gives
Understanding the role played by protic ionic liquids (PILs) and the substituent effect for enhancing the generation of Z-cinnamic acid derivatives†
作者:Rocío B. Rodríguez、Ramiro L. Zapata、María L. Salum、Rosa Erra-Balsells
DOI:10.1039/d0pp00072h
日期:2020.6
Photoisomerization of a series of substituted E-cinnamic acids in MeCN in their acid forms and as their corresponding protic ionic liquids (PILs) with light of 300 nm is studied. The nature, strength, number, and position effects of substituents on the photochemical behavior of E-cinnamic derivatives are investigated. The photosensitization of the reaction in the presence of Michler's ketone is also