- Electrophilic alkylation of arenes with 5-bromopyrimidine en route to 4-aryl-5-alkynylpyrimidines
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A new synthetic protocol for preparation of medicinally important 4-aryl-5-alkynylpyrimidines is described. The featured approach involves a sequence of chemo- and regioselective Br?nsted acid-catalyzed electrophilic alkylation of arenes with 5-bromopyrimidine, followed by oxidative re-aromatization of the formed dihydropyrimidine ring. Finally, palladium-catalyzed Sonogashira cross-coupling reaction provided an end-game strategy.
- Aksenov, Alexander V.,Domenyuk, Dmitriy A.,Magometov, Artyom Yu.,Rubin, Michael,Shcherbakov, Stanislav S.,Shcherbakova, Viktoriia Yu.,Zelensky, Vladimir A.
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- Effect of chloride and sulfate ions on the advanced photo Fenton and modified photo Fenton degradation process of Alizarin Red S
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The degradation of Alizarin Red S (ARS) was carried out by heterogeneous advanced photo Fenton processes (HAPFP) of the type Fe0/H 2O2/UV and heterogeneous modified photo Fenton process (HMPFP) of the type Fe0/ammonium persulfate (APS)/UV. The influence of various reaction parameters like pH, catalyst loading, concentration of the oxidants and the influence of inorganic anions such as Chloride (Cl-) and Sulfate (SO42-) ions on processes were investigated. Quenching of the hydroxyl radical by inorganic anions was confirmed by the decrease in the degradation rate constant for the HAPFP from 3.33 × 10-2 to 0.19 × 10-2 (for Cl- (1 M)) and 0.29 × 10-2 min-1 (for SO42- (1 M)). Similar decrease in rate constant for HMPFP is from 4.67 × 10 -2 to 0.41 × 10-2(for Cl- (1 M)) and 0.51 × 10-2 min-1 (for SO42- (1 M)) process. The combined effect of concentration of sulfate and chloride ions on the rate constant for the degradation of ARS with APS and H2O 2 as oxidants is investigated. The initial degradation mechanism involves the cleavage of a quinone group to catechol as detected by UV-visible and GC-MS analysis.
- Devi, L. Gomathi,Munikrishnappa,Nagaraj,Rajashekhar, K. Eraiah
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p. 125 - 131
(2013/06/27)
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- Process for preparing a synthetic aluminium tanning agent
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A novel synthetic aluminium tanning agent as an alternative for chromium based tanning salts without using formaldehyde was prepared by using aromatic polymeric matrix and aluminium (III) salts as raw materials with suitable masking agents. The preparation of the syntan consists of sulphonation of aromatic molecule, which is incorporated with a polymeric network along with ligands specially designed for the complexation of aluminium (III) salts. The complex can be used as a self-tanning agent in leather industry with fairly good filling behavior. The tanned leathers exhibit shrinkage temperature about 85° C. Due to the higher precipitation point of the product, it can be used for tanning directly after deliming thus eliminating the pickling process. This product, unlike the conventional phenol based products, does not undergo photo-oxidation thereby preventing the discoloration of the tanned leathers.
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- Process for the preparation of acyloxybenzenesulfonic acid or salt thereof
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In preparing an acyloxybenzenesulfonic acid or salts thereof by sulfonating the corresponding acyloxybenzene (1), the preparation process of the acyloxybenzenesulfonic acid wherein as an additive is added at least one selected from among carboxylic acids or esters thereof (2), alkyl phosphates (3), polyphosphoric acids (4), amides and like compounds (6), carbonic esters (7), and hydroxy compounds (8). By the process, acyloxybenzenesulfonic acid excellent in hue can be prepared on an industrial scale in an enhanced yield at enhanced selectivity and lowered cost as compared with the processes of the prior art.
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- THE DESULFONATION OF PHENOLSULFONIC ACIDS IN AQUEOUS SODIUM HYDROGEN SULFATE MIXTURES
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Phenol and phenolsulfonic acids are rapidly sulfonated and desulfonated in aqueous sodium hydrogen sulfate, with or without added sulfuric acid.At temperatures above 130 deg C, desulfonation competes with sulfonation sufficiently to allow steam stripping of phenol from the reaction mixtures, even under conditions of low water content.Above 170 deg C removal of phenol is less efficient because the water content is very low and the predominant species in the reaction mixture is 2,4,6-phenoltrisulfonate.Key words: Phenol; phenolsulfonic acid sulfonation; desulfonation; sodium hydrogen sulfate; kinetics; HPLC.
- Jason, Mark E.
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- A practical regiospecific synthesis of ortho- and meta-hydroxybenzenesulfonic acids
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The first regiospecific route to the ortho-hydroxybenzenesulfonic acid and competitive way to its meta regioisomer are reported.Both compounds were obtained from the silylation of the corresponding chlorophenols, followed by sulfonation of the arylsilane intermediates.Keywords: silylation / sulfonation / chlorophenols / hydroxybenezensulfonic acids
- Babin, P.,Bennetau, B.,Bourgeois, P.,Rajarison, F.,Dunogues, J.
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- Sulfonation of anisole, phenol, toluene and related alkyl and alkoxy derivatives with SO3. The influence of the solvent system on the reactivity and the sulfonic acid product distribution
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The reactions of anisole (1), phenol (2), the alkoxy- and alkylphenyl ethers 3-11, toluene (12) and the o-dialkylbenzenes 13-15 with sulfur trioxide in dichloromethane or trichlorofluoromethane have been studied.Our results have been compared with those obtained with the same substrates upon reaction with SO3 in nitromethane and dioxane.We show that ortho substitution is enhanced for sterically unhindered phenyl ethers and phenols due to complex formation between SO3 and the C(sp2)-bonded oxygen when dichloromethane is used as solvent instead of nitromethane or dioxane.This is mainly as a result of intramolecular SO3 transfer from the oxygen to the ortho carbon and subsequent conversion of the resulting ?-complex into the ortho sulfonic acid.
- Ansink, Harold R. W.,Cerfontain, Hans
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p. 183 - 187
(2007/10/02)
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- Divalent metal salts of sulfonated novolak resins and methods for treating fibrous polyamide materials therewith
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Compositions comprising normally solid, water-soluble divalent metal salts of partially sulfonated novolak resins are provided. These divalent salts of partially sulfonated novolak resins ae useful for imparting to fibrous polyamide materials stain resistance to natural and synthetic acid colorants. Also provided are methods of preparing these resins, methods of treating fibrous polyamide materials with these resins, and fibrous polyamide materials so treated.
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- Process for aryl-quinone and aryl-naphthoquinone diazide sulfonic acids
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A process for the preparation of aryl-diazide-sulfonic acids by a series of sequential in-situ process steps. The process comprises the nitrosation of a hydroxyarylsulfonic acid; conversion of the nitroso-derivative to a sulfamate which is then diazotized to the diazide. Temperature and pH are maintained in predetermined ranges to maintain the reaction products in solution without the formation side-products or the need to isolate intermediates. The process of the invention is particularly useful in the preparation of light-sensitive materials such as naphthoquinonediazide sulfonic acids which are used in the preparation of photoresist compositions. The invention provides a high purity product at a high material efficiency, high equipment utilization, low effluent discharge, and reduced cost.
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- Aromatic Sulphonation. Part 91. The Sulphonation of Anisole, Phenol, Phenyl Methanesulphonate, Potassium Phenyl Sulphate, and a Series of Methyl-, Bromo-, and Chloro-substituted Anisoles and Phenols in Concentrated Aqueous Sulphuric Acid
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The (homogeneous) sulphonation of a number of aromatic ethers and alcohols, viz. anisole (1), 3-methyl- (2), 4-methyl- (3), 2-bromo- (4), 4-bromo- (5), 2-chloro- (6), and 4-chloro-anisole (7), phenol (8), 2-methyl- (9), 3-methyl- (10), 4-methyl- (11), 4-bromo- (12), 2-chloro- (13), and 4-chloro-phenol (14), phenyl methanesulphonate (15), and potassium phenyl sulphate (16) in concentrated aqueous sulphuric acid at 25.0 deg C has been studied, and rates and isomer distributions have been determined.The sulphonation is first-order in the aromatic substrate, and from the rate measurements it is concluded that the species undergoing sulphonation in the phenyl ring is an unprotonated substrate species.In the lower acid concentrations the sulphonating entity is H3SO4(1+).With increasing sulphuric acid concentration there is a gradual change-over in the sulphonating entity from H3SO4(1+) to H2S2O7.The acid concentrations of equal rate contribution by the two entities for anisole and phenol are 87 and 90 +/- 1percent, respectively.Sulphonation on the oxygen atom (i.e., sulphation) does not occur.The o/p-ratios for (1) and (8) do not vary over the studied sulphuric acid range of 75-90percent H2SO4.Partial rate factors for the 2- and 4-position of (1) and (8) are reported.The very low partial rate factors for the 4-substitution of (1) and (8) and the observed extreme suppression and compression of the reactivities of the substrates (1)-(14) are ascribed to hydrogen bonding of the substrates with the acidic solvent species present.It is tentatively suggested that the relatively high contents of sulphonation ortho to -OR with anisole (36percent) and phenol (48percent) are due to specific complexation of the substrates with the sulphonating electrophile.
- Cerfontain, Hans,Lambrechts, Hans J. A.,Schaasberg-Nienhuis, Zwaan R. H.,Coombes, Robert G.,Hadjigeorgiou, Panicos,Tucker, Geoffrey
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p. 659 - 668
(2007/10/02)
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- Method of making substituted hydroquinones
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Substituted quinones are catalytically hydrogenated in the presence of a mixture of (1) low unbranched alcohols and (2) hydrocarbons which are inert and fluid under the conditions of the hydrogenation reaction and which may be aromatic, aliphatic or cycloaliphatic to economically produce corresponding substituted hydroquinones of high purity and low discoloration and in high yields thereof.
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