- Solid-state reaction mechanisms in monomer-dimer interconversions of p-bromonitrosobenzene. Single-crystal-to-single-crystal photodissociation and formation of new non-van der Waals close contacts
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Thermal and photochemical reactions and the phase transition mechanisms of solid-state monomer-dimer interconversions of p-bromonitrosobenzene were studied on the basis of kinetics data and single-crystal-to-single-crystal transformations. From the crystal structure and packing of p- bromobenzeneazodioxide and the previously determined structure of the freshly sublimed monomer, we have explained both consecutive steps in thermal dimerization. While the first reaction (formation of the metastable dimer) with first-order kinetics affords diminishing of the (2 2 0) critical crystal plane that intersects atoms of the nitroso groups, the second phase transformation step includes four critical planes, which show sigmoid kinetics. In the new phase growth, these crystal planes developed in two (Cartesian) dimensions as vectors perpendicular to ab and ac planes, which is in agreement with the dimensionality previously determined on the basis of the Avrami-Erofeyev analysis (with m = 2.01). Photochromic dissociation of the azodioxide at 100 K was followed by structure determination of the single-crystal-to-single-crystal transformation. A new metastable monomer was discovered, in which, despite bond breaking, the nitrogen atoms of the neighboring monomers remained very close to each other (2.30 A), i.e., 23.3% closer than is the sum of two N-atom van der Waals radii. Such an extraordinary close contact was also observed between N and O atoms. This tight packing can explain why the return to dimerization after the low temperature photodissociation occurs so rapidly at a temperature as low as 170 K.
- Halasz, Ivan,Mestrovic, Ernest,Cicak, Helena,Mihalic, Zlatko,Vancik, Hrvoj
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- Synthesis of Di(hetero)arylamines from Nitrosoarenes and Boronic Acids: A General, Mild, and Transition-Metal-Free Coupling
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The synthesis of di(hetero)arylamines by a transition-metal-free cross-coupling between nitrosoarenes and boronic acids is reported. The procedure is experimentally simple, fast, mild, and scalable and has a wide functional group tolerance, including carbonyls, nitro, halogens, free OH and NH groups. It also permits the synthesis of sterically hindered compounds.
- Roscales, Silvia,Csák?, Aurelio G.
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supporting information
p. 1667 - 1671
(2018/03/23)
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- Synthesis of Nitrosobenzene Derivatives via Nitrosodesilylation Reaction
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The electrophilic ipso-substitution of trimethylsilyl-substituted benzene derivatives into nitrosobenzene derivatives is reported. The optimization of the reaction conditions was performed for moderately electron-deficient, electron-rich, and sterically hindered starting materials by varying reaction time, temperature, and equivalents of NOBF4. Also, a stable intermediate of the nitrosation reaction could be characterized by 19F NMR which can be assigned to a NO+ adduct with the nitrosobenzene derivative. This complex decomposes upon aqueous workup and liberates the desired nitrosobenzene derivative.
- Kohlmeyer, Corinna,Klüppel, Maike,Hilt, Gerhard
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p. 3915 - 3920
(2018/04/14)
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- Para-Selective Halogenation of Nitrosoarenes with Copper(II) Halides
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The para-selective direct bromination and chlorination of nitrosoarenes with copper(II) bromide and chloride is reported. Under mild reaction conditions, a range of halogenated arylnitroso compounds are obtained in moderate to good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of a one-pot procedure to obtain the corresponding para-halogenated aniline- and nitrobenzene derivatives.
- Van Der Werf, Angela,Selander, Nicklas
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supporting information
p. 6210 - 6213
(2016/01/09)
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- Crystal disordering and organic solid-state reactions
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This work is the extension of our preliminary communication about the relationship between the change in the solid-state structure and the chemical reaction in a crystal. The investigation is a case study about the nature of the adiabatic organic solid-st
- Varga, Katarina,Volari, Jana,Vanik, Hrvoj
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p. 1434 - 1438
(2015/02/19)
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- Mechanosynthesis of nitrosobenzenes: A proof-of-principle study in combining solvent-free synthesis with solvent-free separations
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Mechanochemical Oxone oxidation of selected para-substituted anilines was used as a rapid and solvent-free route to nitrosobenzenes; besides avoiding bulk solvents and short reaction times, this method exploits high vapour pressures of nitrosobenzenes for the solvent-free separation of the product by sublimation, demonstrating an entirely solvent-free route to chemical synthesis and product isolation. The Royal Society of Chemistry.
- Huskic, Igor,Halasz, Ivan,Friscic, Tomislav,Vancik, Hrvoj
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supporting information
p. 1597 - 1600
(2013/02/23)
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- Nitrosation of aryl and heteroaryltrifluoroborates with nitrosonium tetrafluoroborate
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Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture-sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper, we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF4). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups.
- Molander, Gary A.,Cavalcanti, Livia N.
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experimental part
p. 4402 - 4413
(2012/06/18)
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- Influence of 1,3-dichloroacetone on the regularities of decay of arylnitroso oxides
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The decay kinetics of isomeric forms of a series of arylnitroso oxides in the presence of 1,3-dichloroacetone in acetonitrile was studied by the flash photolysis technique. The regularities observed are explained by the complex formation between the molecules of nitroso oxide and additive.
- Chainikova,Safiullin
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p. 2437 - 2442
(2014/05/06)
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- In situ generation of nitroso compounds from catalytic hydrogen peroxide oxidation of primary aromatic amines and their one-pot use in hetero-Diels-Alder reactions
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A method for in situ generation of nitroso compounds from organoselenium-catalyzed oxidation of anilines by hydrogen peroxide was developed. The generated nitroso compounds were subsequently used in hetero-Diels-Alder reactions. A variety of oxazines were synthesized in reasonable to good yields by this one-pot procedure using primary aromatic amines with different substituents and various conjugated dienes. This strategy might facilitate the current methodologies for nitroso chemistry since no isolation or purification of the nitroso compounds is required. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Zhao, Dongbo,Johansson, Mikael,Baeckvall, Jan-E.
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p. 4431 - 4436
(2008/04/13)
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- Reaction of dimethyldioxirane with aniline hydrohalides
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Oxidation of aromatic amine hydrohalides (aniline hydrochloride, hydrobromide, and hydrofluoride; 4-methylaniline hydrochloride and hydrobromide; 3-methylaniline and N,N-diethylaniline hydrochlorides) with dimethyldioxirane was studied. The product composition was analyzed in relation to the reactant ratio.
- Ivanova,Grabovskii,Kabal'nova,Shereshovets
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p. 2101 - 2105
(2007/10/03)
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- Structural investigations of C-nitrosobenzenes. Part 1. Solution state 1H NMR studies
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Ambient and low temperature 1H NMR spectra of a wide range of 3- and 4-monosubstituted, and some di- and tri-substituted C-nitrosobenzenes have enabled -N=O substituent constants for the static and rotating ring molecules to be calculated. This has provided information on the shielding anisotropy of the N=O group which in turn leads to the firm identification of the monomeric and dimeric solution species. In all cases lowering the solution temperature enhances the relative populations of dimers to monomers, with the (Z)-azodioxy dimer being preferred over the (E)-form, irrespective of the nature of the solid state dimeric structure.
- Fletcher, Daniel A.,Gowenlock, Brian G.,Orrell, Keith G.
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p. 2201 - 2205
(2007/10/03)
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- Azoxy compound
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An azoxy compound represented by the following general formula STR1 wherein R1 denotes a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkoxy group, a lower alkoxy-lower alkoxy group or a group of the formula X1 --C C--CH
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