37841-25-1Relevant academic research and scientific papers
Elimination reactions of (E)-2,4,6-trinitrobenzaldehyde O-benzoyloximes promoted by R2NH/R2NH2+ in 70 mol% MeCN (aq). Effects of the β-aryl group and leaving group on nitrile-forming transition states
Pyun, Sang Yong,Paik, Kyu Cheol,Han, Man So,Cho, Bong Rae
, p. 871 - 876 (2016/06/14)
Elimination reactions of (E)-2,4,6-(NO2)3C6H2CH=NOC(O)C6H4X (3) promoted by R2NH/R2NH2+ in 70 mol% MeCN (aq) have been studied. The reactions produced elimination products and exhibited second-order kinetics. The β and |β1g| values remained nearly the same for all leaving groups and bases. The results can be described by the negligible pxy interaction coefficient, pxy = ?β/?pKlg = ?βlg/?pKBH ≈ 0, which provides a strong support for the (E1cb)irr mechanism. For eliminations from (E)-ArCH NOC=(O)C6H4X (1, 3) and (E)-2,4,6-(NO2)3C6H2CH=NOAr′ (2, 3), the change of the β-aryl group (Ar) from 2,4-dinitrophenyl (1) to 2,4,6-trinitrophenyl (3) increased the rate by 270-fold without appreciable change in the transition state structure. On the other hand, the leaving group (OAr′) variation from benzoate (3) to 4-nitrophenoxy (2) induced a change in reaction mechanism from (E1cb)irr to E2. These results have been attributed to the cyclic transition state for the nitrile-forming eliminations involving the benzoate leaving group.
Elimination of nitrile from (E)-2,4,6-trinitrobenzaldehyde O-pivaloyloxime promoted by R2NH in MeCN. Effect of β-aryl group on the nitrile-forming transition-state
Pyun, S.-Yong
body text, p. 371 - 375 (2011/08/03)
Nitrile-forming eliminations from (E)-2,4,6-(NO2) 3C6H2CH=NOC(O)(CH3)3 promoted by R2NH in MeCN have been studied kinetically. The reactions are second-order and exhibit substantial Hammett ρ and Broensted β values. The k 2 value for elimination from (E)-2,4,6- trinitrobenzaldehyde O-pivaloyloxime promoted by i-Pr2NH in MeCN falls on a single line in the Hammett plot for different β-aryl substituents, which have been shown to react by the E2 mechanism. This result indicated that the reaction mechanism is not changed by the introduction of the 2,4,6-trinitro substituents, and that the elimination reactions from (E)-benzaldehyde O-pivaloyloximes series proceed by the common E2 mechanism.
Elimination reactions of (E)-2,4,6-trinitrobenzaldehyde O-aryloximes promoted by R3N/R3NH+ in 70 mol% MeCN(aq). Effect of β-aryl group the nitrile-forming transition-state
Pyun, Sang Yong,Byun, Woong Sub,Cho, Bong Rae
, p. 1921 - 1924 (2012/01/13)
Nitrile-forming eliminations from (E)-2,4,6-(NO2) 3C6H2CH=NOC6H4-2-X-4- NO2 (1) promoted by R3NH/R3NH+ in 70 mol % MeCN(aq) have been studied kinetically. When X = NO2, the reactions exhibited secondorder kinetics as well as Broensted β = 0.63 and |βlg| = 0.34-0.46, and an E2 mechanism is evident. As the leaving group was made poorer (X = H, Cl, and CF3), Broensted β value increased from 0.63 to 0.85-0.89 without much change in the |βlg| value E2, indicating that structure of the transition state changed to an E1cb-like with extensive Cβ-H bond cleavage, significant negative charge development at the β-carbon, and limited Cα-Oar bond cleavage.
Electrochemically promoted nucleophilic aromatic substitution in room temperature ionic liquids - An environmentally benign way to functionalize nitroaromatic compounds
Cruz, Hugo,Gallardo, Iluminada,Guirado, Gonzalo
experimental part, p. 2531 - 2542 (2011/10/19)
The current manuscript shows the electrochemical studies performed to rationalize the mechanism and develop new green synthetic routes for the synthesis of substituted nitroaromatics based on the advantages of the electrochemical approach to the nucleophilic aromatic substitution reaction (such as (a) low cost and ready availability of reagents, (b) atom economy, (c) high yields, approaching 100%) and the use of Room Temperature Ionic Liquids (RTILs) as green alternative solvents to organic aprotic solvents. Four of the most popular RTILs (1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF 4), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF 6), 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide ([BMIM]TFSI) and 1-butyl-3-methylimidazolium acetate ([BMIM]AcO) have been chosen since they have different properties in terms of solvation effects that can increase the regioselectivity of the reaction. The nucleophiles used to study the feasibility and viability of the reaction were the classical hydride, methoxide, ketones, cyanides and amines, whereas the nitroarenes selected were 4-nitrotoluene, 1,3-dinitrobenzene, 2,4-dinitroaniline, 1,3,5-trinitrobenzene, 1,3-dinitronaphthalene, 1-chloro-2,4,6-trinitrobenzene and 2,4,6- trinitroanisole. The electrocatalysis and regioselectivity effects of using RTILs are also investigated. The article concludes by analyzing the economic cost of performing this electrosynthesis in RTILs and organic solvent electrolyte systems, which contain 0.1 M of supporting electrolyte.
Nucleophilic aromatic substitution of hydrogen: A novel electrochemical approach to the cyanation of nitroarenes
Gallardo, Iluminada
, p. 1759 - 1765 (2007/10/03)
The nucleophilic aromatic substitution of hydrogen through electrochemical oxidation of the intermediate σ complexes (Meisenheimer complexes) in simple nitroaromatic compounds is reported for the first time. The studies have been carried out with hydride and cyanide anions as the nucleophiles using cyclic voltammetry (CV) and preparative electrolysis. The cyclic voltammetry experiments allow for the detection and characterization of the σ complexes and led us to a proposal for the mechanism of the oxidation step. Furthermore, the power of the CV technique in the analysis of the reaction mixture throughout the whole chemical and electrochemical process is described.
Reactivity of Activated Methylene Group in Nitro Compounds. III. Formation of 2,4,6-Trinitrobenzonitrile in the Reaction of 2,4,6-Trinitrotoluene with Carboxylic Acid Chlorides and Anhydrides
Zbarskii, V. L.,Yudin, N. V.,Ivchenko, A. N.,Derevitskaya, A. G.
, p. 1075 - 1076 (2007/10/03)
With the reactions of 2,4,6-trinitrotoluene with carboxylic acid chlorides and anhydrides in the presence of pyridine as examples we showed for the first time that nitrogen atom of a nitro group can be involved in formation of a cyano group.
REACTION OF CYANOTRIMETHYLSILANE WITH POLYNITROAROMATIC FLUORIDES
Chaykovsky, Michael,Adolph, Horst G.
, p. 205 - 210 (2007/10/02)
Cyanotrimethylsilane reacts with polynitroaromatic fluorides to give polynitroaromatic nitriles.
