- Preparation method of 5-halo-2-alkyloxy-4-toluene sulfochloride
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The invention relates to the technical field of chemical material intermediate synthesis, in particular to a preparation method of 5-halo-2-alkyloxy-4-toluene sulfochloride. The 5-halo-2-alkyloxy-4-toluene sulfochloride is formed by taking cheap and avail
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Paragraph 0021; 0027; 0033; 0051; 0055-0057; 0063
(2017/08/29)
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- Selective Halogenation Using an Aniline Catalyst
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Electrophilic halogenation is used to produce a wide variety of halogenated compounds. Previously reported methods have been developed mainly using a reagent-based approach. Unfortunately, a suitable "catalytic" process for halogen transfer reactions has yet to be achieved. In this study, arylamines have been found to generate an N-halo arylamine intermediate, which acts as a highly reactive but selective catalytic electrophilic halogen source. A wide variety of heteroaromatic and aromatic compounds are halogenated using commercially available N-halosuccinimides, for example, NCS, NBS, and NIS, with good to excellent yields and with very high selectivity. In the case of unactivated double bonds, allylic chlorides are obtained under chlorination conditions, whereas bromocyclization occurs for polyolefin. The reactivity of the catalyst can be tuned by varying the electronic properties of the arene moiety of catalyst.
- Samanta, Ramesh C.,Yamamoto, Hisashi
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supporting information
p. 11976 - 11979
(2015/08/18)
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- Selective O-methylation of phenols and benzyl alcohols in simple pyridinium based ionic liquids
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Synthesis of pyridinium based ionic liquids were reported and applied as catalyst for the selective O-methylation of phenols and benzyl alcohols. The reactions were carried out by using dimethylcarbonate (DMC) as the methylating agent. High selectivity, high yield and recyclability of the ionic liquids are important features of the reactions.
- Das, Pranab Jyoti,Das, Jupitara
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- A continuous base-catalyzed methylation of phenols with dimethyl carbonate
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We have found that the use of a conventional, heated, standard 316 stainless steel or steel-braided PTFE tube reactor is a good and easily scalable alternative to the use of continuous microwave-heated reactors. The heat-up is almost as fast as with microwave heating, and the reactors can easily be scaled towards large-scale production. The transfer of the reported microwave procedure to the continuous flow method went very smoothly, and we found that we could further optimize the reaction to a catalytic procedure where only 10 mol % of DBU is needed with only 3 equiv of DMC. The reaction can be run neat in cases where the starting material is soluble in DMC as phenol is, or with a small amount of DMF (2-3 vol). The reaction is efficient for different types of phenols, giving a clean reaction in high yields.
- Tilstam, Ulf
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experimental part
p. 1150 - 1153
(2012/08/27)
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- A continuous methylation of phenols and N, H -heteroaromatic compounds with dimethyl carbonate
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The methylation of phenolic substrates has been reevaluated using sulfolane as solvent instead of DMF. The change of solvent gave in all cases cleaner production of the anisole products in very good yields. The reaction requires 0.1 equiv of DBU, 2-3 equiv of DMC, and 2-5 vols of sulfolane depending on the substrate. At 220 C the reaction time is 10 min. Sulfolane is completely stable under the reaction conditions, excluding unwanted impurities from the solvent. The reaction could also be extended to NH-indole and NH-imidazole derivatives utilizing 0.1 equiv of DBU and 2-3 equiv of DMC in 2 vols of sulfolane. All NH-heteroaromatic compounds gave clean N-methylation.
- Tilstam, Ulf
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p. 1974 - 1978
(2013/02/25)
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- A simple and practical halogenation of activated arenes using potassium halide and oxone in water-acetonitrile medium
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A simple and practical halogenation of activated arenes using a reagent combination of potassium halide and oxone in water-acetonitrile medium is presented. The halogenated products were obtained with good yields and in high purity.
- Tamhankar,Desai,Mane,Wadgaonkar,Bedekar
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p. 2021 - 2027
(2007/10/03)
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- Chemical and in vitro syntheses of brominated and chlorinated 3,4′-dihydroxybibenzyls (halogenated lunularins)
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Ten halogenated lunularins 16, 17, 26, 27, 30, 31, 36, 37, 42 and 43 as model substances for a new class of halometabolites isolated from bryophytes are prepared by chemical total syntheses according to a Wittig-protocol using halogenated aldehydes and ph
- Speicher, Andreas
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p. 162 - 168
(2007/10/03)
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- Chemoselective O-methylation of phenols under non-aqueous condition
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Chemoselective O-methylation of substituted phenols takes place in dry. tetrahydrofuran (THF) in the presence of LiOH.H2O and dimethylsulfate (DMS). Quantitative methyl transfer from DMS preserves the atom economy.
- Basak, Anindita,Nayak, Mrinal K.,Chakraborti, Asit K.
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p. 4883 - 4886
(2007/10/03)
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- Selective aromatic chlorination of activated arenes with sodium chlorite, (salen)manganese(III) complex, and alumina in dichloromethane
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The reaction of alkyl phenyl ethers with sodium chlorite in dichloromethane in the presence of a (salen)manganese(III) complex and alumina preloaded with a small amount of water afforded monochlorination products with unusually high para selectivities under mild conditions. The NaClO2-based biphasic system can also be successfully used for the regioselective monochlorination of substituted anisoles and polymethoxybenzenes.
- Hirano,Yakabe,Monobe,Morimoto
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p. 1905 - 1912
(2007/10/03)
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- SULFONYLAMINOPYRIMIDINES
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A compound of the formula STR1 wherein R 1 to R, R a, R. sup.b X, Y, Z, m and n have the significance given in the description, can be used as medicaments, especially for the treatment and prophylaxix of conditions which are associated with endothelin activities.
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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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- PHENYLATION CATIONIQUE DU CHLORO-4 ANISOLE, ETUDE DE LA MIGRATION DU CHLORE ET DU PHENYLE DANS LES CATIONS IPSO-ARENIUM.
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The phenyl cations obtained from the thermolysis of benzenediazonium tetrafluoroborate react with 4-chlroanisole to give, in addition to phenylation products at position 2 and 3, 2-chloro-4-methoxybiphenyl.The latter is formed by the attack of C6H5(1+) ipso to the chlorine followed by 1,2 migration of the halogen.This rearrangement is totally suppressed in nucleophilic solvents such as dimethylsulfoxide, whereas it is important in heterogeneous conditions.The ability of DMSO to trap the ipso-arenium ions has provided indirect evidence for the attack of C6H5(1+) ipso to the methoxy group. 1-2 migration of the phenyl group has been observed in arenium ions formed by attack of C6H5(1+) ipso to the chlorine and ipso to the methoxy group. 4-methoxybiphenyl and 2,4-dichloroanisole have not been detected by G L C so that dechlorophenylation of 4-chloroanisole must be negligible.
- Pilski, J.,Court, J.,Eustathopoulos, H.,Bonnier, J. M.
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p. 4331 - 4338
(2007/10/02)
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- Hypoglycemic 5-substituted oxazolidine-2,4-diones
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Hypoglycemic 5-phenyl and 5-naphthyl oxazolidine-2,4-diones and the pharmaceutically-acceptable salts thereof; certain 3-acylated derivatives thereof; a method of treating hyperglycemic animals therewith; and intermediates useful in the preparation of said compounds.
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