Search results for "Cyclopentanes"
showing 8 items of 38 documents
Analysis of the Molecular Dialogue Between Gray Mold (Botrytis cinerea) and Grapevine (Vitis vinifera) Reveals a Clear Shift in Defense Mechanisms Du…
2015
Mature grapevine berries at the harvesting stage (MB) are very susceptible to the gray mold fungus Botrytis cinerea, while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infection process developed by B. cinerea on MB versus VB, and the plant defense mechanisms deployed to stop the fungus spreading. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes upregulated during infection of MB are enriched in functional categories related to necrotrophy, such as degradation of the plant cell wall, proteolysis, membrane transport, reactive oxygen species (ROS) genera…
Modulation of the Biological Activity of a Tobacco LTP1 by Lipid Complexation
2004
Plant lipid transfer proteins (LTPs) are small, cysteine-rich proteins secreted into the extracellular space. They belong to the pathogenesis-related proteins (PR-14) family and are believed to be involved in several physiological processes including plant disease resistance, although their precise biological function is still unknown. Here, we show that a recombinant tobacco LTP1 is able to load fatty acids and jasmonic acid. This LTP1 binds to specific plasma membrane sites, previously characterized as elicitin receptors, and is shown to be involved in the activation of plant defense. The biological properties of this LTP1 were compared with those of LTP1-linolenic and LTP1-jasmonic acid…
2-Alkenoyl Pyridine N-Oxides, Highly Efficient Dienophiles for the Enantioselective Cu(II)−Bis(oxazoline) Catalyzed Diels−Alder Reaction
2007
2-Alkenoyl pyridine N-oxides are introduced as a new kind of efficient dienophiles for the Cu(II)−bis(oxazoline) (BOX) catalyzed enantioselective Diels−Alder reaction affording higher reactivity and enantioselectivity (ee's up to 96%) than the corresponding nonoxidized 2-alkenoyl pyridines.
N‐Heterocyclic Carbene Catalyzed Quadruple Domino Reactions: Asymmetric Synthesis of Cyclopenta[ c ]chromenones
2018
An N-heterocyclic carbene catalyzed domino sequence via α,β-unsaturated acyl azolium intermediates has been developed. This strategy provides a convenient enantioselective route to functionalized tricyclic coumarin derivatives and cyclopentanes. DFT studies and control experiments were performed to gain better insight into the reaction mechanism.
Synthesis of Highly Functionalized Cyclopentanes as Precursors of Hydroxylated Azidocarbonucleosides
2009
Regio- and stereoisomers of functionalized azido amino alcohols with a cyclopentane skeleton were synthesized in enantiomerically pure forms. Enzymatic ring cleavage of racemic 2-azabicyclo[2.2.1]hept-5-en-3-one gave the corresponding amino acid and one enantiomer of the lactam stereospecifically. These were protected by esterification and carbamoylation, and then epoxidized. The resulting oxiranes underwent cleavage by sodium azide with complementary stereoselectivities. The regioisomeric products were easily separated by crystallization or column chromatography.
Cyclic fatty acid monomers : synthesis and characterization of methyl w-(2-alkylcyclopentyl) alkenoates and alkanoates
1988
Abstract Some 1,2-disubstituted cyclopentanes were synthesized. These were methyl 9-(2-butyl-cyclopentyl)-8-nonenoate, methyl 7-(2-hexyl-cyclopentyl)-6-heptenoate and methyl 5-(2-octyl-cyclopentyl)-4-pentenoate and their corresponding alkanoates. The synthesis involved a Michael addition of alkylmagnesium bromide to an unsaturated cyclic ester. The resulting cis and trans ethyl 2-alkylcyclopentane carboxylate were further converted to the alcohols then to the aldehydes. The aldehydes were condensed with the ylide derived from the (ω-carboxyalkyl)-triphenylphosphonium bromide and methylsulfinylmethide in DMSO to give unsaturated C18 cyclic fatty acid monomers. These cyclic fatty acids were f…
Role of dioxygenase α-DOX2 and SA in basal response and in hexanoic acid-induced resistance of tomato (Solanum lycopersicum) plants against Botrytis …
2015
Resistance of tomato (Solanum Lycopersicum) to the fungal pathogen Botrytis cinerea requires complex interplay between hormonal signalling. In this study, we explored the involvement of new oxylipins in the tomato basal and induced response to this necrotroph through the functional analysis of the tomato α-dioxygenase2 (α-DOX2)-deficient mutant divaricata. We also investigated the role of SA in the defence response against this necrotrophic fungus using SA-deficient tomato nahG plants. The plants lacking dioxigenase α-DOX2, which catalyses oxylipins production from fatty acids, were more susceptible to Botrytis, and hexanoic acid-induced resistance (Hx-IR) was impaired; hence α-DOX2 is requ…
Chemoselective, Substrate-directed Fluorination of Functionalized Cyclopentane β-Amino Acids
2016
This work describes a substrate-directed fluorination of some highly functionalized cyclopentane derivatives. The cyclic products incorporating CH2 F or CHF2 moieties in their structure have been synthesized from diexo- or diendo-norbornene β-amino acids following a stereocontrolled strategy. The synthetic study was based on an oxidative transformation of the ring carbon-carbon double bond of the norbornene β-amino acids, followed by transformation of the resulted "all cis" and "trans" diformyl intermediates by fluorination with "chemodifferentiation".