- A proposed standard sample for nuclear overhauser effect measurements
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A standard sample for the measurement of proton-proton nuclear Overhauser effects (NOE) is proposed. 1,5-Dichloro-2,4-dimethoxybenzene (DCDMB) shows an essentially full (50%) enhancement of the proton H-3 when the protons of the flanking methoxyl groups a
- Bain, Alex D.,Mazzola, Eugene P.,Page, Samuel W.
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Read Online
- Oxidative Photochlorination of Electron-Rich Arenes via in situ Bromination
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Electron-rich arenes are oxidatively photochlorinated in the presence of catalytic amounts of bromide ions, visible light, and 4CzIPN as organic photoredox catalyst. The substrates are brominated in situ in a first photoredox-catalyzed oxidation step, followed by a photocatalyzed ipso-chlorination, yielding the target compounds in high ortho/para regioselectivity. Dioxygen serves as a green and convenient terminal oxidant. The use of aqueous hydrochloric acid as the chloride source reduces the amount of saline by-products.
- Düsel, Simon Josef Siegfried,K?nig, Burkhard
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supporting information
p. 1491 - 1495
(2019/04/30)
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- Aromatic Halogenation Using N-Halosuccinimide and PhSSiMe3 or PhSSPh
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We developed a mild aromatic halogenation reaction using a combination of N-halosuccinimide and PhSSiMe3 or PhSSPh. Less reactive aromatic compounds, such as methyl 4-methoxybenzoate, were brominated with PhSSiMe3 or PhSSPh and N-bromosuccinimide in high yields. No reaction was observed in the absence of PhSSiMe3 or PhSSPh. This method is also applicable to chlorination reactions using N-chlorosuccinimide and PhSSPh.
- Hirose, Yuuka,Yamazaki, Mirai,Nogata, Misa,Nakamura, Akira,Maegawa, Tomohiro
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p. 7405 - 7410
(2019/06/14)
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- Pyrazolo [3,4 - the b] pyridine and [...] composition preparation method and use of (by machine translation)
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The present invention provides a pyrazolo [3,4 - the b] pyridine and [...] compound of preparation and use, in particular, the present invention provides a following formula (I) compounds are shown, wherein the definition of each group as described in the specification. The compounds of the invention has excellent tyrosine kinase inhibiting activity, so can be used for preparing a series of treating diseases associated with the tyrosine kinase activity of the drug. (by machine translation)
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Paragraph 0230; 0231; 0232; 0233
(2017/07/22)
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- Solvent choice and kinetic isotope effects (KIEs) dramatically alter regioselectivity in the directed ortho metalation (DoM) of 1,5-dichloro-2,4-dimethoxybenzene
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The regioselective formation of the 6-lithio derivative of 1,5-dichloro-2,4-dimethoxybenzene (i.e., 12) by directed ortho metalation (DoM) with nBuLi in THF is described. Although literature reports suggest direct deprotonation at C6, a series of time-course and labelling studies has revealed that deprotonation rather occurs exclusively at C3 followed by isomerization of the anion to C6. By contrast, when DoM was performed in Et 2O, deprotonation again occurred selectively at C3, but now no isomerization occurs, and electrophilic capture produces the regioisomer of that produced in THF. In these labeling studies, it has been found that deuterium has an enormous kinetic isotope effect (KIE) that suppresses not only the original DoM reaction at C3 when deuterium is present there, but also suppresses isomerization to C6 when the label is at that site. Remarkably, this "protectinggroup" role of the deuterium is unique to THF; in ether, full deprotonation of the deuterium at C3 was observed.
- Farmer, Jennifer L.,Froese, Robert D.J.,Lee-Ruff, Edward,Organ, Michael G.
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p. 1888 - 1893
(2015/01/30)
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- Halogenated volatiles from the fungus Geniculosporium and the actinomycete Streptomyces chartreusis
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Two unidentified chlorinated volatiles X and Y were detected in headspace extracts of the fungus Geniculosporium. Their mass spectra pointed to the structures of a chlorodimethoxybenzene for X and a dichlorodimethoxybenzene for Y. The mass spectra of some constitutional isomers for X and Y were included in our databases and proved to be very similar, thus preventing a full structural assignment. For unambiguous structure elucidation all possible constitutional isomers for X and Y were obtained by synthesis or from commercial suppliers. Comparison of mass spectra and GC retention times rigorously established the structures of the two chlorinated volatiles. Chlorinated volatiles are not very widespread, but brominated or even iodinated volatiles are even more rare. Surprisingly, headspace extracts from Streptomyces chartreusis contained methyl 2-iodobenzoate, a new natural product that adds to the small family of iodinated natural products.
- Wang, Tao,Rabe, Patrick,Citron, Christian A.,Dickschat, Jeroen S.
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supporting information
p. 2767 - 2777
(2014/01/06)
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- Metal and H2O2 free aerobic oxidative aromatic halogenation with [RNH3+] [NO3-]/HX and [BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl) as multifunctional ionic liquids
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Novel multifunctional ionic liquids (ILs) are generated by addition of HBr or HCl to alkylammonium nitrates ([RNH3+] [NO 3-]) and to 3-methyl-1-(butyl-4-sulfonyl)imidazolium nitrate ([BMIM(SO3H)][NO3]). The resulting [RNH 3+] [NO3-]/HX and mono (3-methyl-1-(butyl-4-sulfonyl)imidazolium) monohalogenide mononitrate ([BMIM(SO3H)][NO3)x(X)y] (X = Br, Cl)) systems act as solvent and promoter for aerobic oxidative halogenation of arenes under mild conditions in high yields that can be repeated over several cycles.
- Prebil, Rok,Laali, Kenneth K.,Stavber, Stojan
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supporting information
p. 2108 - 2111
(2013/06/05)
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- Bronsted acidic ionic liquid accelerated halogenation of organic compounds with N-halosuccinimides (NXS)
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The Bronsted-Acidic ionic liquid 1-methyl-3-(4-sulfobutyl) imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into a-halo and a,a-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of a-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions.
- Vrazic, Dejan,Jereb, Marjan,Laali, Kenneth K.,Stavber, Stojan
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- Regioselective copper-catalyzed chlorination and bromination of arenes with O2 as the oxidant
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Electron-rich aromatic C-H bonds undergo regioselective chlorination and bromination in the presence of CuX2, LiX (X = Cl, Br) and molecular oxygen. Preliminary mechanistic insights suggest that the bromination and chlorination reactions proceed by different pathways.
- Yang, Lujuan,Lu, Zhan,Stahl, Shannon S.
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supporting information; experimental part
p. 6460 - 6462
(2010/03/04)
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- Selective halogenation of aromatics by dimethyldioxirane and halogen ions
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The oxidation of halogen anions by dimethyldioxirane (DMD) produced reactive species which led, in acidic media, to the halogenation of activated aromatic rings. The reaction can be efficiently controlled to obtain selective and mixed halogenated species.
- Bovicelli,Mincione,Antonioletti,Bernini,Colombari
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p. 2955 - 2963
(2007/10/03)
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- A synthetic equivalent of 3,5-dimethoxyphenyl lithium. A facile route to 5-substituted resorcinols
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Butyl lithium metallates 1,3-dimethoxy-4,6-dichlorobenzene selectively at C-5. The resulting anion reacts effectively with electrophiles.
- Kraus, George A.,Zeng, Yuan
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p. 2133 - 2141
(2007/10/03)
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- Formation and Structure of Bis(2,6-dimethoxyphenyl)nitramine, 2NNO2
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Bis(2,6-dimethoxyphenyl)nitramine (1) was found to be one of the products of the reaction of nitryl chloride, NO2Cl with 2,6-dimethoxyphenyl lithium. 1 was characterized through its NO2 vibrations in the IR spectrum, νas = 1540 cm-1 and νs = 1290 cm-1, and its identity was confirmed by its elemental analysis, 1H and 13C NMR data, and its mass spectrum.According to a single crystal X-ray structure determination, 1 is nearly planar about the central N-N bond; the N-N bond length is 136.3 pm.In addition, two further products of the reaction were also characterized, 1-chloro-2,6-dimethoxybenzene (2) and 2,4-dichloro-1,5-dimethoxybenzene (3). - Keywords: Aryllithium Compounds, Nitryl Chloride, Nitramines, X-Ray Structure
- Heuer, Lutz,Schmutzler, Reinhard,Schomburg, Dietmar
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p. 911 - 916
(2007/10/02)
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- Facile Synthesis of Chloro-substituted Aromatic Ethers by Use of Benzyltrimethylammonium Tetrachloroiodate
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The reaction of aromatic ethers with a calculated amount of benzyltrimethylammonium tetrachloroiodate in acetic acid (or dichloromethane) under mild conditions gave, selectively, the objective chloro-substituted aromatic ethers in good yields.
- Kajigaeshi, Shoji,Shinmasu, Youichi,Fujisaki, Shizuo,Kakinami, Takaaki
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p. 415 - 418
(2007/10/02)
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- Highly Selective Aromatic Chlorinations. Part 2. The Chlorination of Substituted Phenols, Anisoles, Anilines, and Related Compounds with N-Chloroamines in Acidic Solution
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Phenols, anisoles, anilines, and related compounds are chlorinated in trifluoroacetic acid at room temperature by N-chlorodialkylamines and N-chlorotrialkylammonium salts.With monsubstituted compounds and their 2- and 3-substituted derivatives the reaction occurs efficiently and selectively at the 4-position.The reactivity of these substrates and the selectivity of their chlorinations are determined by electronic rather than steric effects of the substituent.Blocking the reaction with a substituent at the 4-position generally leads to only poor or moderate yields of the 2-chlorinated product.Evidence for radical and cation radical intermediates has been obtained in the reactions of some of the 4-substituted reactants and the mechanism of chlorination is discussed in the light of these findings.The reactions of selected substrates have been scaled up to give laboratory syntheses.
- Smith, John R. Lindsay,McKeer, Linda C.,Taylor, Jonathan M.
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p. 385 - 392
(2007/10/02)
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- THE REACTIONS OF UNACTIVATED ARYL HALIDES WITH SODIUM METHOXIDE IN HMPA; SYNTHESIS OF PHENOLS, ANISOLES, AND METHOXYPHENOLS
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Sodium methoxide reacts with dichlorobenzenes in HMPA to give the chloroanisoles as a result of a SNAr process.Excess MeONa then effects the demethylation of the ethers to give the chlorophenols via an SN2 reaction.With tri- and tetrachlorobenzenes the initially formed chloroanisoles can be dealkylated to chlorophenols or can suffer further substitution to give the chlorodimethoxybenzenes; these react with excess MeONa to give the chloromethoxyphenols.The results obtained with the various isomers of the di-, tri-, and tetrachlorobenzenes are presented and discussed on the basis of the electronic effects of the substituents.
- Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Montanucci, M.
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p. 193 - 198
(2007/10/02)
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- Novel Polysulphur Bridged Metacyclophanes from the Iron-catalysed Reaction of Bis-(2,4-dimethoxyphenyl) Sulphide with Disulphur Dichloride. Evidence for the Cleavage of the Carbon-Sulphur Bond by Electrophilic Agents
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The iron-catalysed reaction of bis-(2,4-dimethoxyphenyl)sulphide (3) with disulphur dichloride (S2Cl2) in dilute chloroform solution has been investigated.Surprisingly, the reaction gives 4,6,11,13,18,20-hexamethoxy-1,2,9,16-tetrathiametacyclophane
- Bottino, Francesco,Pappalardo, Sebastiano
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p. 718 - 722
(2007/10/02)
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- SUR LA REACTION ENTRE LE CHLORURE DE PYRIDINIUM ET LES NITROALCANES PRIMAIRES
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The lack of homogeneity in the dealkylation of phenol ethers by pyridinium halides had been overcome in a few cases by the use of solvents such as quinoline.The high dissolving power of nitrohydrocarbons led us to study their behaviour in the presence of pyridinium chloride and of 2-methoxynaphthalene 1, taken as the reference ether.On one hand, nitrobenzene is a good solvent which homogenizes the reaction mixture but slows down the reaction; on the other hand, it is not so with nitroalkanes which quickly interact.Thus, a mixture of 2-methoxynaphthalene 1, nitroethane and pyridinium chloride yields, after refluxing, 1-chloro-2-methoxynaphthalene 2, 1-acetylpyridinium chloride oxime 3, acetic acid, acetohydroxamic acid 5, acetonitrile, acetamide and ammonium chloride, in various proportions according to the relative amounts of reagents or the heating duration.The unusual chlorination of 1 can be carried out with primary nitro-alkanes other than nitroethane.Methyl phenol ethers other than 1 can be halogenated if they have a sufficiently electrophilic position.With this method, we were able to synthesize a few mono- or dichlorinated compounds starting from 1,6- or 1,7-dimethoxynaphthalenes and 5-methoxybenzofuran.The study of the experiments run with varying proportions of reactants or with overaddition of one or the other of the resulting products suggests a few mechanisms.Pyridinium bromide induces the same type of reaction, but with lower yields.
- Dauzonne, Daniel,Demerseman, Pierre,Royer, Rene
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p. 601 - 608
(2007/10/02)
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