54364-08-8Relevant academic research and scientific papers
Photoreaction between benzoylthiophenes and N-BOC-tryptophan methyl ester
Perez-Prieto, Julia,Morant-Minana, Maria C.,Galian, Raquel E.,Miranda, Miguel A.
, p. 231 - 236 (2006)
Drug-induced photoallergy requires as the first step formation of covalent drug-protein photoadducts. One of the key amino acids involved in this process is tryptophan (Trp). In this context, several diaryl ketones, including 2-benzoylthiophene (BT), [2-(5-benzoyl-5-thienyl)]-2-methylpropanoic methyl ester (TPA methyl ester) and 4-(2-thienylcarbonyl)phenyl]-2-methylpropanoic methyl ester (SUP methyl ester) have been irradiated in the presence of N-BOC-(L)-tryptophan methyl ester. Laser flash photolysis has allowed to detect three neutral radicals (ketyl, indolyl and skatolyl radicals) resulting from formal hydrogen-atom abstraction. This correlates well with the isolation of homodimers, as well as with cross-coupling products, in the preparative irradiation. The main cross-coupling products were in all cases lactones arising from the reaction of the Trp-derived skatolyl radicals with the corresponding ketyl radicals. These lactones were obtained as the (4R) stereoisomers with remarkable diasteroselectivity. No coupling products through the phenyl p-position of BT or TPA methyl ester were found. By contrast, ketone homodimers and cross-coupling products arising from reaction through the thienyl 5-position were obtained when using BT and SUP methyl ester; this is very interesting, because stable LAT-derived products are difficult to isolate.
Bifunctional copper-based photocatalyst for reductive pinacol-type couplings
Caron, Antoine,Morin, émilie,Collins, Shawn K.
, p. 9458 - 9464 (2019/10/11)
A bifunctional copper-based photocatalyst has been prepared that employs a pyrazole-pyridine ligand incorporating a sulfonamide moiety that functions as an intramolecular hydrogen-bond donor for a photochemical PCET process. In typical reductive PCET processes, the photocatalyst and H-bond donor must have an appropriate redox potential and pKa, respectively, to promote the PCET. When working in concert in a bifunctional catalyst such as Cu(pypzs)(BINAP)BF4, the pKa of the H-bond donor can have an acidity that is orders of magnitude less and still efficiently promote the PCET process. A reductive pinacol-type coupling can be performed using a base-metal derived photocatalyst to afford valuable diols (24 examples, 46-99% yield), from readily available aldehydes and ketones.
