Visible-Light Induced Thiol–Ene Reaction on Natural Lignin

2017 ◽  
Vol 5 (10) ◽  
pp. 9160-9168 ◽  
Author(s):  
Hailing Liu ◽  
Hoyong Chung
Keyword(s):  
Visible Light ◽  
Ene Reaction ◽  
Natural Lignin

Nitrobenzoxadiazole-labelled polyisoprenoid alcohols

1996 ◽  
Vol 74 (12) ◽  
pp. 2531-2535 ◽  
Author(s):  
Bruce J. Balcom ◽  
Nils O. Petersen
Keyword(s):  
Carboxylic Acid ◽  
Visible Light ◽  
Singlet Oxygen ◽  
Key Words ◽  
Acid Derivative ◽  
Coupling Reaction ◽  
Double Bonds ◽  
Ene Reaction ◽  
Fluorescence Labelling ◽  
Carboxylic Acid Derivative

We have prepared, isolated, and characterized a series of nitrobenzoxadiazole labelled polyisoprenoid alcohols. The coupling reaction employed was a dicyclohexylcarbodiimide mediated condensation between a carboxylic acid derivative of nitrobenzoxadiazole and the polyisoprenoid alcohols citronellol, solanesol, and dolichol. Upon exposure to visible light, a self-sensitized singlet oxygen "ene" reaction oxidized double bonds in the isoprene moiety. The rate of oxidation is greatly reduced in solvents where singlet oxygen is short-lived. Key words: nitrobenzoxadiazole, isoprenoid, dolichol, citronellol, solanesol, fluorescence labelling, singlet oxygen, ene reaction.

Investigating eosin Y as a photocatalyst for the radical-dependent activity-based probing of deubiquitinating enzymes

2021 ◽  
Vol 19 (10) ◽  
pp. 2177-2181
Author(s):  
Neil C. Taylor ◽  
Joanna F. McGouran
Keyword(s):  
Visible Light ◽  
Eosin Y ◽  
Deubiquitinating Enzymes ◽  
Protein Thiol ◽  
Free Oxygen ◽  
Ene Reaction ◽  
Metal Free ◽  
System P ◽  
Dependent Activity

Assessment of the eosin Y initiated protein–protein thiol–ene reaction in a metal-free, oxygen-tolerant, visible-light mediated system.

scholarly journals Radical Functionalization of Thioglycosides in Aqueous Medium

2020 ◽  
Author(s):  
Sarbjeet Kaur ◽  
dominic luciano ◽  
gaoyuan zhao ◽  
Ting Wang
Keyword(s):  
Visible Light ◽  
Aqueous Medium ◽  
Reaction Medium ◽  
Reaction Pathways ◽  
Buffer System ◽  
Ene Reaction ◽  
Thiyl Radicals ◽  
Disulfide Formation ◽  
Basic Reaction ◽  
Radical Functionalization

<p>A visible-light-mediated thiol-ene reaction is successfully operated in aqueous medium. Organic photoredox catalyst (9-mesityl-10-methylacridinum tetrafluoroborate) is used to initiate the radical process to generate thiyl radicals upon light irradiation. Two reaction pathways are discovered in different aqueous buffer system. Thiol-ene adduct is preferred in acidity reaction medium; while disulfide formation is found to be favored in basic reaction medium. Moreover, a visible-light-mediated modified Danishefsky-Wan desulfurization is used to convert thioglycoside to highly substituted tetrahydropyran ring.</p>

Visible light-induced thiol-ene reaction: A new strategy to prepare Α,ω-dithiol and Α,ω-divinyl telechelic polythiolether oligomers

2015 ◽  
Vol 54 (6) ◽  
pp. 740-749 ◽  
Author(s):  
Wenchao Ma ◽  
Dong Chen ◽  
Lianying Liu ◽  
Yuhong Ma ◽  
Li Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Ene Reaction ◽  
New Strategy

Radical Functionalization of Thioglycosides in Aqueous Medium

2020 ◽  
Author(s):  
Sarbjeet Kaur ◽  
dominic luciano ◽  
gaoyuan zhao ◽  
Ting Wang
Keyword(s):  
Visible Light ◽  
Aqueous Medium ◽  
Reaction Medium ◽  
Reaction Pathways ◽  
Buffer System ◽  
Ene Reaction ◽  
Thiyl Radicals ◽  
Disulfide Formation ◽  
Basic Reaction ◽  
Radical Functionalization

<p>A visible-light-mediated thiol-ene reaction is successfully operated in aqueous medium. Organic photoredox catalyst (9-mesityl-10-methylacridinum tetrafluoroborate) is used to initiate the radical process to generate thiyl radicals upon light irradiation. Two reaction pathways are discovered in different aqueous buffer system. Thiol-ene adduct is preferred in acidity reaction medium; while disulfide formation is found to be favored in basic reaction medium. Moreover, a visible-light-mediated modified Danishefsky-Wan desulfurization is used to convert thioglycoside to highly substituted tetrahydropyran ring.</p>

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

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