Xn:Harmful;
127-06-0Relevant articles and documents
Rates of Formation of Iminium Ions from Acetone and Monoprotonated 2-pyrrolidine
Hine, Jack,Evangelista, Ramon A.
, p. 3890 - 3892 (1980)
The kinetics of the reaction of 2-pyrrolidine (1) with acetone has been studied by experiments in which the reversibly formed iminium ion is captured irreversibly by hydroxylamine.From experiments over the pH range 8.5-10.6 rate constants for iminium ion formation from 1 and 1-H+ were obtained.These rate constants were smaller than the corresponding rate constant for pyrrolidine, but the value for 1-H+ was large enough to show that the intermediate carbinolamine was undergoing internal acid-catalyzed dehydration to give the iminium ion.
Metal-free artificial nucleases based on simple oxime and hydroxylamine scaffolds
Fernandes, Luciano,Fischer, Franciele L.,Ribeiro, Carolina W.,Silveira, Gustavo P.,Sa, Marcus M.,Nome, Faruk,Terenzi, Hernan
, p. 4499 - 4502 (2008)
Hydrolysis of DNA is of increasing importance in biotechnology and medicine. In this Letter, we present the DNA-cleavage potential of metal-free hydroxylamines and oximes as new members of nucleic acid cleavage agents.
Selective synthesis of dimethyl ketone oxime through ammoximation over Ti-MOR catalyst
Ding, Jianghong,Wu, Peng
, p. 86 - 95 (2014)
Titanosilicate with the MOR topology (Ti-MOR), postsynthesized from highly dealuminated mordenite and TiCl4 vapor through a solid–gas reaction, was highly active and selective for the liquid-phase ammoximation of dimethyl ketone (DMK) with ammonia and hydrogen peroxide. The parameters effecting the formation of the ammoximation product of dimethyl ketone oxime were investigated systematically in a batch-type reactor, and the optimized conditions were further applied to continuous ammoximation of DMK in a slurry reactor. Ti-MOR was superior to other titanosilicates in terms of activity and lifetime. TS-1 was not suitable for the ammoximation of DMK, whereas Ti-MWW required a higher catalyst loading to reach a reasonable activity, and they both easily produced a main byproduct of oxidative coupling of dimethyl ketone oxime. The deactivation behavior of Ti-MOR was investigated. Ammonia-induced structural desilication and accompanied Ti sites migration altered a more serious influence on the catalyst duration than coke deposition during continuous ammoximation.
Stereochemical and electronic interaction studies of α-heterosubstituted acetone oximes
Olivato, P. R.,Ribeiro, D. S.,Rittner, R.,Hase, Y.,Pra del, D.,Bombieri, G.
, p. 1479 - 1496 (1995)
The free νC=N bands in the IR spectra of some α-heterosubstituted acetone oximes show the existence of only a monomeric form in chloroform solutions below 1E-2 M, while in carbon tetrachloride self-associated species are also present.The 1H and 13C NMR chemical shift data indicate the predominance of the E over the Z isomer.The ΔνC=N frequency shifts and molecular mechanics strongly suggest that the oximes are in the gauche conformation.X-ray diffraction data have shown that the single dimethylaminoacetone oxime isomer exists in the E configuration and gauche conformation.Non-additivity effects for the α-methylene carbon chemi cal shifts seem to indicate the occurence of a ?C=N/?*C-x interaction besides the ?*C=N/?C-X hyperconjugative interaction.
Influences of fluorine implantation on catalytic performance and porosity of MOR-type titanosilicate
Yang, Yulin,Ding, Jianghong,Wang, Binshen,Wu, Jing,Zhao, Chen,Gao, Guohua,Wu, Peng
, p. 160 - 169 (2014)
Fluorine species were implanted into the framework of Ti-MOR by post-treatment with fluorides in order to modify the microenvironment around Ti active sites and then to improve their catalytic activity in liquid-phase oxidation. The effects of NH4F amount, fluorination temperature, and solvent on the catalytic performance of F-Ti-MOR were investigated in detail. Methanol was found to be superior to water in fluorination. Fluorine implantation increased the electropositivity of Ti active sites through forming SiO3/2F units in the neighborhood, which enhanced the catalytic performance in the ammoximation of cyclohexanone remarkably. F-Ti-MOR prepared under optimized fluorination conditions showed a cyclohexanone conversion of 99% in comparison to only 30% conversion given by primitive Ti-MOR. Meanwhile, the implanted fluorine species captured the organic molecules with a relatively large dimension tightly, creating enormous steric hindrances that prevented other molecules, in particular those with bulky molecular dimensions, from diffusing into channels freely. Thus, F-Ti-MOR showed much lower activity than Ti-MOR in the hydroxylation of aromatics.
Kinetics and mechanism of the copper-catalysed oxygenation of 2-nitropropane
Balogh-Hergovich, Eva,Greczi, Zoltan,Kaizer, Jozsef,Speier, Gabor,Reglier, Marius,Giorgi, Michel,Parkanyi, Laszlo
, p. 1687 - 1696 (2002)
Primary and secondary nitro compounds react with dioxygen in the presence of copper metal and N ligands such as N,N,N′,N′-tetramethylethylenediamine (tmeda), 2,2′-bipyridine (bpy), and 1,10-phenantroline (phen) in various solvents to form aldehydes or ketones. More coordinating solvents as well as donor N ligands accelerate the reaction remarkably. The oxygenolysis of 2-nitropropane (NPH) in the presence of copper and tmeda in DMF results in acetone and acetone oxime. The amount of tmeda influences the chemoselectivity, higher tmeda concentrations preferentially lead to the formation of the oxime. The kinetics of the reaction, measured at 90 °C, resulted in a rate equation of first-order dependence on copper and dioxygen and second-order dependence on 2-nitropropane. The rate constant, activation enthalpy, and entropy at 363.16 K are as follows: kcat = (5.37 ± 0.34) × 10-2 Mol-3 dm9 s-1, Ea = 131 ± 4 kJ mol-1, ΔH? = 127 ± 4 kJ mol-1 and ΔS? = 80 ± 13 J mol-1 K-1. The catalytically active intermediates CuII(NP)2(tmeda) and CuII(NO2)2(tmeda) in the catalytic cycle were isolated and their structures determined by X-ray crystallography. The kinetics of the stoichiometric oxygenation of CuII(NP)2(tmeda) to CuII(NO2)2(tmeda) and acetone resulted in the overall second-order rate equation with a rate constant, activation enthalpy, and entropy at 313.16 K of ks = 0.46 ± 0.02 mol-1 dm3 s-1, Ea = 38 ± 1 kJ mol-1, ΔH? = 35 ± 1 kJ mol-1 and ΔS? = -142 ± 13 J mol-1 K-1, respectively. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Cyclization of N-allylthiourea derivatives by the action of α-chloronitrosoalkanes
Tkachenko,Pushin,Sokolov,Fedoseev,Martynov
, p. 347 - 350 (1998)
A convenient method is proposed for obtaining difficultly available derivatives of 2-amino-5-chloromethyl-2-thiazoline by the cyclization of N-allylthioureas under the action of α-chloronitrosoalkanes. It is assumed that the reaction proceeds as a halogenophilic process leading to the intermediate formamidinesulfenyl chloride which is rapidly and selectively cyclized with the formation of 2-amino-2-thiazoline derivatives. 1998 Plenum Publishing Corporation.
Six-at-Once Dedeuteration of Acetone-d6 in the Presence of 3-exo--2-exo-norbornanamine
Hine, Jack,Tsay, Hwai-Min
, p. 3797 - 3802 (1983)
3-exo--2-exo-norbornanamine (2) was prepared and used as a catalyst in aqueous solution at 35 degC for the dedeuteration of acetone-d6.Monoprotonated 2 acts as an effective catalyst by transforming the ketone to an iminium ion and then using its dimethylamino group to dedeuterate the iminium ion by internal basic catalysis.At pH 9.95 the most common result of iminium-ion formation is the exchange of all six deuterium atoms.This requires a mechanism for cis-trans isomerization of the intermediate iminium ion.The gem-diamine mechanism proposed earlier for iminium ions derived from cyclopentanone helps explain why 2 gives six-at-once exchange while some rather similar diamines do not.The kinetics of iminium-ion formation from 2 and acetone were studied by the hydroxylamine-capture technique.The rates of iminium-ion formation thus obtained are reasonably consistent with those obtained in the deuterium exchange experiments.
Nickel-Catalyzed NO Group Transfer Coupled with NOxConversion
Padmanaban, Sudakar,Choi, Jonghoon,Vazquez-Lima, Hugo,Ko, Donghwi,Yoo, Dagyum,Gwak, Jinseong,Cho, Kyung-Bin,Lee, Yunho
supporting information, p. 4585 - 4593 (2022/03/02)
Nitrogen oxide (NOx) conversion is an important process for balancing the global nitrogen cycle. Distinct from the biological NOx transformation, we have devised a synthetic approach to this issue by utilizing a bifunctional metal catalyst for producing value-added products from NOx. Here, we present a novel catalysis based on a Ni pincer system, effectively converting Ni-NOx to Ni-NO via deoxygenation with CO(g). This is followed by transfer of the in situ generated nitroso group to organic substrates, which favorably occurs at the flattened Ni(I)-NO site via its nucleophilic reaction. Successful catalytic production of oximes from benzyl halides using NaNO2 is presented with a turnover number of >200 under mild conditions. In a key step of the catalysis, a nickel(I)-?NO species effectively activates alkyl halides, which is carefully evaluated by both experimental and theoretical methods. Our nickel catalyst effectively fulfills a dual purpose, namely, deoxygenating NOx anions and catalyzing C-N coupling.
Rhodium(III)-Catalyzed Direct C-H Arylation of Various Acyclic Enamides with Arylsilanes
Li, Xiaolan,Sun, Kai,Shen, Wenjuan,Zhang, Yong,Lu, Ming-Zhu,Luo, Xuzhong,Luo, Haiqing
supporting information, p. 31 - 36 (2021/01/09)
The stereoselective β-C(sp2)-H arylation of various acyclic enamides with arylsilanes via Rh(III)-catalyzed cross-coupling reaction was illustrated. The methodology was characterized by extraordinary efficacy and stereoselectivity, a wide scope of substrates, good functional group tolerance, and the adoption of environmentally friendly arylsilanes. The utility of this present method was evidenced by the gram-scale synthesis and further elaboration of the product. In addition, Rh(III)-catalyzed C-H activation is considered to be the critical step in the reaction mechanism.
