10229-55-7Relevant academic research and scientific papers
Transition-Metal-Free Trifluoromethylation of Aldehyde Derivatives with Sodium Trifluoromethanesulfinate
Tan, Zheng,Zhang, Shiwei,Zhang, Yan,Li, Yunpeng,Ni, Minjie,Feng, Bainian
, p. 9384 - 9399 (2017/09/23)
A metal-free and cost-effective synthetic protocol for the trifluoromethylation of N,N-disubstituted hydrazones with Langlois's reagent (CF3SO2Na) to afford the corresponding functionalized trifluoromethyl ketone hydrazones has been established. It is proposed that a radical/SET mechanism proceeding via a trifluoroalkyl radical may be involved in the reaction. Applications of the methodology in industry will be found and the development of new methods for trifluoromethylation with Langlois's reagent will be continued in our laboratory.
Mechanistic aspects of the formation of aldehydes and nitriles in photosensitized reactions of aldoxime ethers
Peter De Lijser,Rangel, Natalie Ann,Tetalman, Michelle A.,Tsai, Chao-Kuan
, p. 4126 - 4134 (2008/02/04)
(Chemical Equation Presented) The photooxidation of a series of aldoxime ethers was studied by laser flash photolysis and steady-state (product studies) methods. Nanosecond laser flash photolysis studies have shown that chloranu (CA)-sensitized reactions of the O-methyl (1), O-ethyl (2), O-benzyl (3), and O-tert-butyl (4) benzaldehyde oximes result in the formation of the corresponding radical cations. In polar non-nucleophilic solvents such as acetonitrile, there are several follow-up pathways available depending on the structure of the aldoxime ether and the energetics of the reaction pathway. When the free energy of electron transfer (ΔGET) becomes endothermic, syn-anti isomerization is the dominant pathway. This isomerization pathway is a result of triplet energy transfer from CA to the aldoxime ether. For substrates with α-protons (aldoxime ethers 1-3), the follow-up reactions involve deprotonation at the α-position followed by β-scission to form the benziminyl radical (and an aldehyde). The benziminyl radical reacts to give benzaldehyde, the major product under these conditions. A small amount of benzonitrile is also observed. In the absence of α-hydrogens (aldoxime ether 4), the major product is benzonitrile, which is thought to occur via reaction of the excited (triplet) sensitizer with the aldoxime ether. Abstraction of the iminyl hydrogen yields an imidoyl radical, which undergoes a β-scission to yield benzonitrile. An alternative pathway involving electron transfer followed by removal of the iminyl proton was not deemed viable based on charge densities obtained from DFT (B3LYP/6-31G*) calculations. Similarly, a rearrangement pathway involving an intramolecular hydrogen atom transfer process was ruled out through experiments with a deuterium-labeled benzaldehyde oxime ether. Studies involving nucleophilic solvents have shown that all aldoxime ethers reacted with MeOH by clean second-order kinetics with rate constants of 0.7 to 1.2 × 107 M-1 s-1, which suggests that there is only a small steric effect in these reactions. The steady-state experiments demonstrated that under these conditions no nitrile is formed. This is explained by a mechanistic scheme involving nucleophilic attack on the nitrogen of the aldoxime ether radical cation, followed by solvent-assisted [1,3]-proton transfer and elimination of an alcohol, similar to the results obtained for a series of acetophenone oxime ethers.
Imine exchange in O-aryl and O-alkyl oximes as a base reaction for aqueous 'dynamic' combinatorial libraries. A kinetic and thermodynamic study
Polyakov, Vladimir A.,Nelen, Marina I.,Nazarpack-Kandlousy, Noureddin,Ryabov, Alexander D.,Eliseev, Alexey V.
, p. 357 - 363 (2007/10/03)
Kinetics and mechanisms of the imine exchange reactions of O-alkyl and O-aryl oximes with O-alkyl-and O-aryloxyamines, respectively, were studied by 1H NMR spectroscopy in aqueous solutions. The reaction between benzaldehyde O-methyloxime and O-ethylhydroxylamine at 60 °C is first order in both oxime and the alkoxylamine (the second-order rate constant k2 = 0.86 ± 0.081 mol-1 min-1 at pD 2.9). the reaction being subject to acidic catalysis. A similar imine transfer was studied in the reaction of 1,3-diaminooxyprog with bifunctional oximes. Testing of various additives as potential catalysts for the reaction revealed imidazole as a moderately effective catalyst. The exchange in O-aryl oximes was studied in the interaction between 3-pyridinealdehyde O-pnenyloxime and O-(p-nitrophenyl)hydroxylamine. The reaction is first order in the oxime, but its is independent on the aryloxyamine concentration and pD. The proposed mechanism involves a rate-limiting hydration of the oxime molecule. Mechanisms of the exchange reactions are discussed in relation to their possible use to generate diverse pools of compounds for the recently proposed 'dynamic' combinatorial chemistry approach Copyright
