- Designed To React: Terminal Copper Nitrenes and Their Application in Catalytic C?H Aminations
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Heteroscorpionate ligands of the bis(pyrazolyl)methane family have been applied in the stabilisation of terminal copper tosyl nitrenes. These species are highly active intermediates in the copper-catalysed direct C?H amination and nitrene transfer. Novel perfluoroalkyl-pyrazolyl- and pyridinyl-containing ligands were synthesized to coordinate to a reactive copper nitrene centre. Four distinct copper tosyl nitrenes were prepared at low temperatures by the reaction with SO2tBuPhINTs and copper(I) acetonitrile complexes. Their stoichiometric reactivity has been elucidated regarding the imination of phosphines and the aziridination of styrenes. The formation and thermal decay of the copper nitrenes were investigated by UV/Vis spectroscopy of the highly coloured species. Additionally, the compounds were studied by cryo-UHR-ESI mass spectrometry and DFT calculations. In addition, a mild catalytic procedure has been developed where the copper nitrene precursors enable the C?H amination of cyclohexane and toluene and the aziridination of styrenes.
- Moegling, Julian,Hoffmann, Alexander,Thomas, Fabian,Orth, Nicole,Liebh?user, Patricia,Herber, Ulrich,Rampmaier, Robert,Stanek, Julia,Fink, Gerhard,Ivanovi?-Burmazovi?, Ivana,Herres-Pawlis, Sonja
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supporting information
p. 9154 - 9159
(2018/07/25)
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- Improved Halogenation of Methyl Aromatics and Methyl Heteroaromatics: Unexpected Reactivity of Tetrahalogeno-diphenylglycolurils
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1,3,4,6-Tetrachloro (TCDGU) and 1,3,4,6-tetrabromo-3α,6α-diphenylglycolurils smooth halogen oxidizers have been exploited in a new direction as reagents for free radical substitution toward some N-halosuccinimide nonreactive bis-heterocycles. An unexpected selectivity and reactivity were observed with methyl benzenes, methyl heterocycles, and methyl-bis-heterocycles of interest. A chemometric study has been performed to optimize five independent factors of the chlorination reaction with TCDGU. The predictive model was established either for the halogenation conversion and the ratio of monochlorination.
- Moretti, Florian,Poisson, Guillaume,Marsura, Alain
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p. 173 - 183
(2016/05/19)
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- Selectivity towards hydrodehalogenation and dehalo-coupling in the reduction of trichloromethyl derivatives with iron(II) chloride
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The reductive electron transfer (ET) induced on a series of RCCl3 derivatives by iron(II) chloride has been studied.The main reaction products are the homocoupling dimer, RCCl2-CCl2R, and the H/Cl substitution derivative, RCHCl2, and the majority of the compounds examined exhibit a highly selective tendency to form just one of these products.As a general rule, the RCHCl2 compound is the main product when the R group contains substituents which make further reduction of the radical to the carbanion easier and behave as ligands towards the iron(II) ion.In the other cases, the dimer RCCl2-CCl2R is the main product.A few exceptions are found, and these are discussed in view of the possible effects of the R moiety on the different possible routes for the reaction products.The presence of unsaturated derivatives, RCCl=CClR (E/Z mixture), was observed in the case of the reactions where the homocoupling product was also obtained and is ascribed, on the basis of experimental evidence, to a dehalogenation mechanism of the dimer RCCl2-CCl2R assisted by the iron(II) ion.
- Folli, Ugo,Goldoni, Francesca,Iarossi, Dario,Sbardellati, Silvia,Taddei, Ferdinando
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p. 1017 - 1020
(2007/10/02)
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- FREE RADICAL CHLORINATION OF METHYL DERIVATIVES OF PYRIDINE, PYRAZINE, AND THIAZOLE BY N-CHLOROSUCCINIMDE
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When methylazines (2-, 3-, and 4-methylpyridines, methylpyrazine) are treated with N-chlorosuccinimide they undergo successive chlorination of the methyl group to give 2-chloromethylpyridine, 2-dichloromethylpyridine, and dichloromethylpyrazine in preparative yields. 3-Dichloromethylpyridine was synthesized from pyridine-3-aldehyde and PCl5.The primary chlorination products of 4-methylthiazole are 4-methyl-5-chlorothiazole and 5-chloro-4-chloromethylthiazole.
- Rubina, K. I.,Iovel', I. G.,Gol'dberg, Yu. Sh.,Shimanskaya, F. V.
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p. 454 - 457
(2007/10/02)
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- Studies on Ketene and Its Derivatives. CXIII. Reaction of Dichloroketene with Aromatic Amine N-Oxides
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Reaction of dichloroketene with pyridine 1-oxide (1) gave four products, namely, 2-dichloromethylpyridine (2), 4-dichloromethylpyridine (3), 3,3,7-trichloro-6-dichloroacetyl-2-oxo-2,3,3a,6,7,7a-hexahydrofuropyridine (4), and 3,3-dichloro-6-dichloroacetyl-7-hydroxy-2-oxo-2,3,3a,6,7,7a-hexahydrofuropyridine (5).Reaction of dichloroketene with 1, followed by treatment with abs. methanol gave 3, methyl 2,2-dichloro-2-(2-pyridyl)acetate (6), and methyl 2,2-dichloro-2-(4-pyridyl)acetate (7).Similar reaction of dichloroketene with methylpyridine 1-oxides gave the corresponding 2-dichloro and 4-dichloro methylpyridines.On the other hand, reaction of dichloroketene with 2,6-dimethylpyridine 1-oxide (18), followed by treatment with abs. methanol gave 4-dichloromethyl-2,6-dimethylpyridine (19) and bis(2,6-dimethyl-4-pyridyl)dichloromethane (21).Dichloroketene also reacted with quinoline 1-oxide (24) and isoquinoline 2-oxide (29) to give the corresponding dichloromethyl derivatives (25 and 26, and 30, respectively).Keywords --- aromatic amine N-oxide; dichloroketene; dichloromethylpyridine; dichloromethylquinoline; dichloromethylisoquinoline
- Katagiri, Nobuya,Niwa, Ryuji,Furuya, Yoichi,Kato, Tetsuzo
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p. 1833 - 1841
(2007/10/02)
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- THE PREPARATION OF 4- AND 6-CHLORO-2-CHLOROMETHYLPYRIDINE
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6-Chloro-2-chloromethylpyridine is prepared from 6-chloro-2-methylpyridine by a route in which the 2-Me substituent was successively converted to 2-acetoxymethyl, 2-hydroxymethyl and finaly to the required 2-chloromethyl substituent.Attempts to simultaneously monochlorinate the Me group and reduce the N-oxide function of 6-chloro-2-methylpyridine-N-oxide with methanesulphonyl chloride and p-toluenesulphonyl chloride gave only very small yields of 6-chloro-2-chloromethyl-pyridine. 4-Chloro-2-chloromethylpyridine is prepared from 2-methylpyridine-N-oxide by nitration, followed by substitution of the 4-nitro group by chloro using conc HCl; side chain chlorination of the 2-Me group using p-toluenesulphonyl chloride yields 4-chloro-2-chloromethylpyridine.Phosphoryl chloride reacts with 2-chloromethylpyridine-N-oxide hydrochloride to yield only 14.4percent of 4-chloro-2-chloromethylpyridine, together with 2-chloromethylpyridine (2.2percent), 2-dichloromethylpyridine (41.6percent) and 6-chloro-2-chloromethylpyridine (41.8percent).Attempts to N-oxidise 2-chloromethylpyridine with peracids led to either 2-hydroxymethylpyridine (peracetic, m-chloroperbenzoic and performic acid) or no reaction (perfluoroacetic acid); none of the peracids led to any detectable N-oxidation.
- Barnes, John H.,Hartley, Frank R.,Jones, Christopher E. L.
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p. 3277 - 3280
(2007/10/02)
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- The Reactions of 1,2,3-Triazolopyridine with Electrophiles
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On treatment with chlorine, bromine, or mercuric acetate triazolopyridine (1) gives dichloromethyl-, dibromomethyl-, and alkoxy(alkoxymercurio)methyl-pyridines (3), (4), (5), and (8) with loss of nitrogen.Nitration gives 3-nitrotriazolopyridine (9), which on reduction gives 3-(2-pyridyl)imidazopyridine (11).The mechanism of formation of these compounds is discussed.
- Jones, Gurnos,Sliskovic, D. Robert,Foster, Beverley,Rogers, John,Smith, Anthony K.,et al.
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