scholarly journals Theoretical Study of the Reaction Formalhydrazone with Singlet Oxygen. Fragmentation of the C=N Bond, Ene Reaction and Other Processes

2013 ◽  
Vol 90 (2) ◽  
pp. 431-438 ◽  
Author(s):  
Benjamin Rudshteyn ◽  
Álvaro Castillo ◽  
Ashwini A. Ghogare ◽  
Joel F. Liebman ◽  
Alexander Greer
Keyword(s):  
Singlet Oxygen ◽  
Theoretical Study ◽  
Ene Reaction

scholarly journals Photooxidation of 2-(tert-Butyl)-3-Methyl-2,3,5,6,7,8-Hexahydroquinazolin-4(1H)-one, an Example of Singlet Oxygen ene Reaction

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5008
Author(s):  
Adrian Méndez ◽  
Jonathan Román Valdez-Camacho ◽  
Jaime Escalante
Keyword(s):  
Singlet Oxygen ◽  
Theoretical Study ◽  
Solvent Mixture ◽  
Ambient Conditions ◽  
Ene Reactions ◽  
Ene Reaction ◽  
Photo Oxidation ◽  
Tert Butyl ◽  
Nmr Study ◽  
Step Mechanism

Singlet oxygen ene reactions produce 2-(tert-butyl)-4a-hydroperoxy-3-methyl-2,4a, 5,6,7,8-hexahydroquinazolin-4(3H)-one quantitatively during diffusion crystallization of 2-(tert-butyl)-3-methyl-2,3,5,6,7,8-hexahydroquinazolin-4(1H)-one in n-hexane/CH2Cl2 solvent mixture. To confirm this photo-oxidation, a 1H-NMR study in CDCl3 was performed with exposure to ambient conditions (light and oxygen), with neither additional reactants nor catalysts. A theoretical study at the B3LyP/6311++G** level using the QST2 method of locating transition states suggests a two-step mechanism where the intermediate, which unexpectedly did not come from the peroxide intermediate, has a low activation energy.

Photooxygenation in polymer matrices: En route to highly active antimalarial peroxides

2005 ◽  
Vol 77 (6) ◽  
pp. 1059-1074 ◽  
Author(s):  
Axel G. Griesbeck ◽  
Tamer T. El-Idreesy ◽  
Anna Bartoschek
Keyword(s):  
Singlet Oxygen ◽  
Protoporphyrin Ix ◽  
Polymer Matrices ◽  
Allylic Alcohols ◽  
Ene Reaction ◽  
Highly Active ◽  
Determining Factors ◽  
Broad Variety ◽  
Covalently Linked

Photooxygenation involving the first excited singlet state of molecular oxygen is a versatile method for the generation of a multitude of oxy-functionalized target molecules often with high regio- and stereoselectivities. The efficiency of singlet-oxygen reactions is largely dependent on the nonradiative deactivation paths, mainly induced by the solvent and the substrate intrinsically. The intrinsic (physical) quenching properties as well as the selectivity-determining factors of the (chemical) quenching can be modified by adjusting the microenvironment of the reactive substrate. Tetraarylporphyrins or protoporphyrin IX were embedded in polystyrene (PS) beads and in polymer films or covalently linked into PS during emulsion polymerization. These polymer matrices are suitable for a broad variety of (solvent-free) photooxygenation reactions. One specific example discussed in detail is the ene reaction of singlet oxygen with chiral allylic alcohols yielding unsaturated β-hydroperoxy alcohols in (threo) diastereoselectivities, which depended on the polarity and hydrogen-bonding capacity of the polymer matrix. These products were applied for the synthesis of mono- and spirobicyclic 1,2,4-trioxanes, molecules that showed moderate to high antimalarial properties. Subsequent structure optimization resulted in in vitro activities that surpassed that of the naturally occurring sesquiterpene-peroxide artemisinin.

Regioselectivity of the Singlet Oxygen Ene Reaction (Schenck Reaction) with Vinylsilanes

1994 ◽  
Vol 59 (12) ◽  
pp. 3335-3340 ◽  
Author(s):  
Waldemar Adam ◽  
Markus J. Richter
Keyword(s):  
Singlet Oxygen ◽  
Ene Reaction

scholarly journals Experimental and Theoretical Study of the Stability of the Complex Fisetin–Cu(II) and A Comparative Study of Free Ligand and Complex Interaction with Molecular Singlet Oxygen

2020 ◽  
Vol 96 (4) ◽  
pp. 815-825
Author(s):  
Vanesa A. Muñoz ◽  
Frida C. D. Dimarco Palencia ◽  
Matias I. Sancho ◽  
Sandra Miskoski ◽  
Norman A. García ◽  
...  
Keyword(s):  
Comparative Study ◽  
Singlet Oxygen ◽  
Theoretical Study ◽  
Free Ligand ◽  
Complex Interaction ◽  
The Stability ◽  
Molecular Singlet Oxygen

ChemInform Abstract: STEREOCHEMISTRY OF THE SINGLET OXYGEN, ENE REACTION WITH OLEFINS

1974 ◽  
Vol 5 (4) ◽  
pp. no-no
Author(s):  
L. M. STEPHENSON ◽  
D. E. MCCLURE ◽  
P. K. SYSAK
Keyword(s):  
Singlet Oxygen ◽  
Ene Reaction
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