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.
Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of<i>N</i>-Nosylhydrazones as Diazo Surrogate
作者:Zhaohong Liu、Binbin Liu、Xue-Feng Zhao、Yan-Bo Wu、Xihe Bi
DOI:10.1002/ejoc.201601610
日期:2017.1.26
The cross-olefination reaction of donor and acceptor diazocompounds is reported. The use of N-nosylhydrazones as the diazo surrogates and the dependence on silver catalysis are crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, affording functionalized alkenes in good-to-high yields with moderate Z/E selectivity
1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine
作者:Courtney C. Aldrich、Joseph A. Buonomo、Malcolm S. Cole、Carter G. Eiden
DOI:10.1055/s-0040-1707345
日期:2020.12
variants of the Wittig olefination, Appel halogenation, and Staudingerreduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalyticStaudingerreductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters
Iron(IV)-corrole complexes were first investigated as catalysts for olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine. Efficient olefination of aromatic aldehydes with high trans-selectivity was observed, showing iron corrole is a new kind of promising catalyst for olefination reaction. Transformation of the phosphazine to ylide by iron(IV) corrole was proved to
BF<sub>3</sub>·OEt<sub>2</sub>-mediated syn-selective Meyer–Schuster rearrangement of phenoxy propargyl alcohols for Z-β-aryl-α,β-unsaturated esters
作者:Surendra Puri、Madala Hari Babu、Maddi Sridhar Reddy
DOI:10.1039/c6ob01090c
日期:——
1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer–Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
We synthesized azo dye- and fluorescence-labeled cis-cinnamic acid analogues possessing inhibitory activity agaihst lettuce root growth and a trans-isomer without bioactivity as a control probe. The radicles incubated with the azo dye-labeled analogue were stained red, with their tips especially deeply dyed. The fluorescent images of the radicles incubated with each of these molecular probes depicted that the root cap was fluorescence-stained. However, images of the control radicles prepared by staining with the trans-isomer fluorescent probe did not show emission at the root cap. These contrasts suggest specific localization of the cis-cinnamate analogue at the columella cells. (C) 2016 Elsevier Ltd. All rights reserved.