5912-44-7Relevant articles and documents
Palladium-catalyzed Suzuki-Miyaura coupling of amides by carbon-nitrogen cleavage: General strategy for amide N-C bond activation
Meng, Guangrong,Szostak, Michal
supporting information, p. 5690 - 5707 (2016/07/06)
The first palladium-catalyzed Suzuki-Miyaura cross-coupling of amides with boronic acids for the synthesis of ketones by sterically-controlled N-C bond activation is reported. The transformation is characterized by operational simplicity using bench-stable, commercial reagents and catalysts, and a broad substrate scope, including substrates with electron-donating and withdrawing groups on both coupling partners, steric-hindrance, heterocycles, halides, esters and ketones. The scope and limitations are presented in the synthesis of >60 functionalized ketones. Mechanistic studies provide insight into the catalytic cycle of the cross-coupling, including the first experimental evidence for Pd insertion into the amide N-C bond. The synthetic utility is showcased by a gram-scale cross-coupling and cross-coupling at room temperature. Most importantly, this process provides a blueprint for the development of a plethora of metal catalyzed reactions of typically inert amide bonds via acyl-metal intermediates. A unified strategy for amide bond activation to enable metal insertion into N-C amide bond is outlined (Scheme 1).
Mechanism of lipid peroxidation photosensitized by tiaprofenic acid: Product studies using linoleic acid and 1,4-Cyclohexadienes as model substrates
Samadi, Abdelouahid,Martinez, Luis A.,Miranda, Miguel A.,Morera, Isabel M.
, p. 359 - 365 (2007/10/03)
A careful study of the linoleic acid hydroperoxide (LOOH) profile obtained upon peroxidation of linoleic acid (LA) photosensitized by tiaprofenic acid (TPA) and analogous ketones has been undertaken to distinguish between type-I and type-II photoperoxidation mechanisms. 1,4-Cyclohexadiene and 1,2-dimethylcyclohexa-2,5-diene-carboxylic acid (CHDCA) have also been used as models for LA since they also have double allylic systems. Coir-radiation of LA with TPA and decarboxytiaprofenic acid (DTPA) in acetonitrile and micellar media produced significant amounts of conjugated dienic LOOH. The cis,trans to trans,trans ratio depended on the irradiation time; thus, this parameter is an ambiguous tool for mechanistic assignment. An interesting finding was the decrease of the LOOH level after long irradiation times in mixtures photooxidized by DTPA, which is attributed to quenching of the DTPA triplet by the generated dienic LOOH. High-performance liquid chromatography analyses confirmed that the main pathway operating in photodynamic lipid peroxidation sensitized by (D)TPA is a type-I mechanism. However, product studies using CHDCA have clearly shown that a type-II mechanism is also operating and might contribute to the overall photooxidation process in a significant way.
Photochemistry of tiaprofenic acid, a nonsteroidal anti-inflammatory drug with phototoxic side effects
Bosca,Miranda,Vargas
, p. 181 - 182 (2007/10/02)
The phototoxic nonsteroidal anti-inflammatory drug tiaprofenic acid (1) is photolabile under aerobic conditions. Irradiation of a methanol solution of 1 under oxygen produces the photoproducts 2, 3, 4, and 5, and also produces a singlet oxygen as evidenced by trapping with 2,5-dimethylfuran.
