1575-61-7Relevant articles and documents
Synthesis and characterization of a Gd(III) based contrast agent responsive to thiol containing compounds
Carrera, Carla,Digilio, Giuseppe,Baroni, Simona,Burgio, Daniela,Consol, Simona,Fedeli, Franco,Longo, Dario,Mortillaro, Armando,Aime, Silvio
, p. 4980 - 4987 (2007)
A novel Gd(iii) complex with a modified DO3A-like chelating cage has been synthesized and characterized as a candidate contrast agent responsive to the concentration of free thiols in tissues (essentially represented by reduced glutathione, GSH). The novel compound (called Gd-DO3AS-Act) bears a flexible linker ending with a 2-pyridyl-dithio group, that can promptly react with free thiols (XSH) to form mixed disulfides of the form Gd-DO3AS-SX. Compound Gd-DO3AS-Act is characterized by a millimolar relaxivity as high as 8.1 mM -1 s-1 (at 20 MHz, 25 °C and pH 7.4). Upon reaction with GSH, the Gd-DO3AS-SG covalent adduct is formed and the millimolar relaxivity drops to 4.1 mM-1 s-1. Such a decrease in relaxivity is explained on the basis of the formation of an intramolecular coordinative bond between one of the glutathionyl carboxyl groups and the Gd(iii) centre, lowering the hydration state of the paramagnetic centre. 1H-NMR dispersion profiles together with 17O-NMR transverse relaxation time versus temperature profiles confirm that the hydration of the Gd(iii) centre is strongly reduced ongoing from Gd-DO3AS-Act to the Gd-DO3AS-SG adduct. The relaxivity difference brought about by the reaction of Gd-DO3AS-Act with GSH can be enhanced up to 60% in the presence of poly-β-cyclodextrin. This journal is The Royal Society of Chemistry.
Synthesis of N-trifluoromethyl amides from carboxylic acids
Flavell, Robert R.,Liu, Jianbo,Parker, Matthew F. L.,Toste, F. Dean,Wang, Sinan,Wilson, David M.
supporting information, p. 2245 - 2255 (2021/08/12)
Found in biomolecules, pharmaceuticals, and agrochemicals, amide-containing molecules are ubiquitous in nature, and their derivatization represents a significant methodological goal in fluorine chemistry. Trifluoromethyl amides have emerged as important functional groups frequently found in pharmaceutical compounds. To date, there is no strategy for synthesizing N-trifluoromethyl amides from abundant organic carboxylic acid derivatives, which are ideal starting materials in amide synthesis. Here, we report the synthesis of N-trifluoromethyl amides from carboxylic acid halides and esters under mild conditions via isothiocyanates in the presence of silver fluoride at room temperature. Through this strategy, isothiocyanates are desulfurized with AgF, and then the formed derivative is acylated to afford N-trifluoromethyl amides, including previously inaccessible structures. This method shows broad scope, provides a platform for rapidly generating N-trifluoromethyl amides by virtue of the diversity and availability of both reaction partners, and should find application in the modification of advanced intermediates.
Intramolecular Cyclization of Brominated Oxime Ether Promoted with Ytterbium(0) to the Synthesis of Cyclic Imines
Wang, Yiqiong,Huang, Fei,Zhang, Songlin
supporting information, p. 5178 - 5181 (2020/08/13)
The first utility of ytterbium(0) as a mediating-metal in the intramolecular cyclization of brominated oxime ether was reported in this paper. In contrast to the prior methods, the N–O bond was used as a receptor of nucleophilic reagent, rather than as a source of N-centered radicals. Cyclic imines were obtained in this one-pot reaction with a broad scope of substrates and feasible reaction conditions.
