Carboxyl radical-assisted 1,5-aryl migration through Smiles rearrangement
作者:Asik Hossian、Ranjan Jana
DOI:10.1039/c6ob01758d
日期:——
We report herein, a silver(I)-catalyzed Smiles rearrangement of 2-aryloxy- or 2-(arylthio)benzoic acids to provide aryl-2-hydroxybenzoate or aryl-2-mercaptobenzoate dimer, respectively, through 1,5-aryl migration from oxygen or sulfur to carboxylate oxygen. Mechanistically, the aryl ether moiety undergoes an intramolecular ipso attack by the carboxyl radical followed by a C–O or C–S bond cleavage.
A photoredox-neutral Smiles rearrangement of 2-aryloxybenzoic acids
作者:Jose. C. Gonzalez-Gomez、Nieves P. Ramirez、Teresa Lana-Villarreal、Pedro Bonete
DOI:10.1039/c7ob02579c
日期:——
We report on the use of visible light photoredox catalysis for the radical Smilesrearrangement of 2-aryloxybenzoic acids to obtain aryl salicylates. The method is free of noble metals and operationally simple and the reaction can be run under mild batch or flow conditions. Being a redox neutral process, no stoichiometric oxidants or reductants are needed.
We report herein a cerium photocatalyzed aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement. This operationally simple protocol utilizes inexpensive CeCl3 as a photocatalyst and converted a variety of 2-aryloxybenzoic acids into aryl-2-hydroxybenzoates in good yields.
Latent mercaptan stabilizers for improved weatherability of clear halogen-containing polymer compositions
申请人:MORTON INTERNATIONAL, INC.
公开号:EP1004624A1
公开(公告)日:2000-05-31
Stabilizer compositions useful for protecting clear polyvinyl chloride and other clear halogen-containing polymer compositions used in the manufacture of exterior weatherable products against discoloration and degradation caused by exposure to ultraviolet light and weathering in addition to heat comprising a latent mercaptan which degrades during processing of the composition at an elevated temperature to liberate a free mercaptan, in combination with a synergistic amount of a free phenyl salicylate compound. The latent mercaptan may be the sole heat stabilizer additive in the stabilizer composition, but the free mercaptan released during processing may also synergize the activity of organic-based or metal-based heat stabilizers such as metal salts and organometallic stabilizers such as organotin carboxylates and organotin mercaptides in the polymer composition.
Clear polyvinyl chloride and other clear halogen-containing polymer compositions containing these compounds are also provided which exhibit improved ultraviolet light stability and weatherability without detracting from their thermal performance.
Stabilizers for improved weatherability of clear polyvinyl chloride compositions
申请人:ROHM AND HAAS COMPANY
公开号:EP1004625A1
公开(公告)日:2000-05-31
Stabilizer compositions that useful for protecting clear polyvinyl chloride and other clear halogenated polymer compositions against discoloration and degradation caused by exposure to light and weathering in addition to heat comprising an organotin compound selected from the group consisting of organotin mercaptides, sulfides of organotin mercaptides, organotin sulfides, and/or organotin carboxylates, and a free phenyl salicylate compound. These stabilizers offer improved ultraviolet light stability and weatherability to clear polyvinyl chloride resins designed for weatherable applications without detracting from the desired thermal performance.
Clear polyvinyl chloride resin and other clear halogenated polymer compositions are also provided, containing these compounds.