88-44-8Relevant articles and documents
Development of an efficient ruthenium catalyzed synthetic process and mechanism for the facile conversion of benzothiazoles to orthanilic acids
Jagadeesh,Karthikeyan,Nithya,Sandhya, Y. Sree,Reddy, S. Sudhaker,Reddy, P. Pradeep Kumar,Kumar, M. Vinod,Charan, K.T. Prabhu,Narender,Bhagat
experimental part, p. 99 - 107 (2010/12/18)
Ruthenium-Schiff base complex catalyzed efficient protocol has been developed for the synthesis of orthanilic acids from benzothiazoles in good to excellent yields using N-haloamines. Hexa-coordinated ruthenium complex with Schiff base and triphenylphosphine ligands has been prepared and its catalytic function was invented for the synthesis of orthanilic acids. The synthetic process utilizes our efficient method for the selective and preferential oxidation of thiazole ring of benzothiazoles using N-haloamines without effecting phenyl ring. The detailed catalytic, mechanistic and kinetic investigations have been made for the synthetic reactions. Solvent isotope studies have been made in H2O-D2O and the reactions were carried out at different temperatures. Under the identical set of conditions, the kinetics of catalyzed reactions has been compared with uncatalyzed reactions and found that the catalyzed reactions are 9-11 folds faster. The catalytic constants (KC) have been calculated for each N-haloamine at different temperatures and the values of activation parameters with respect to the catalyst have been evaluated. Spectroscopic evidence for the formation of 1:1 complex between N-haloamine and ruthenium has been obtained. The observed results have been explained by a plausible mechanism and the related rate law has been deduced.
Preparation, crystal structure and microwave studies on ring-substituted arylammonium hydrogen sulfate salts
Kapoor,Srivastava, Pratibha,Singh, Gurdip,Froehlich, Roland
, p. 1283 - 1288 (2008/09/18)
Three ring substituted arylammonium hydrogen sulfates (RSAHS)/ring substituted dianilinium sulfates (RDAS) have been prepared from corresponding arylamines by treatment with excess conc. H2SO4 and characterized by X-ray crystallography, elemental, gravimetric and spectral analyses. The RSAHS/RDAS salts yield the corresponding ring substituted amino benzene sulfonic acids (RSABSA) when subjected to microwave irradiation. It is observed that these salts undergo transformation to acid in solid state via proton transfer reaction prior to sulfonation.
A study on the sulfonation of aromatic amines with sulfuric acid under microwave irradiation
Li, Hui-Zhang,Xiao, Li-Wei,Li, Hong-Ya,Wang, Kai-Fang,Li, Xu
, p. 493 - 494 (2007/10/03)
The sulfonation of aromatic amines with high yields, simple operations and short reaction time has been studied under microwave irradiation in solvent-free conditions.
Effect of substituent in diazotized orthanilic acid on the azo coupling with 7-acetylamino-4-hydroxynaphthalene-2-sulfonic acid in citrate-phosphate buffers
Kornev,Zheltov
, p. 1095 - 1099 (2007/10/03)
Effect of substituent in the para position with respect to the diazo group in diazotized orthanilic acid derivatives on the rate and selectivity of azo coupling with 7-acetylamino-4-hydroxynaphthalene-2-sulfonic acid was studied in citrate-phosphate buffers. The selectivity of azo coupling at the 3-position of the azo component almost does not depend on the nature of electron-donor substituent. Electron-acceptor groups considerably reduce the selectivity of formation of the 3-isomer. Previous conclusions, according to which the rate-determining stages are different depending on the site of azo coupling of diazotized orthanilic acid with 7-acetylamino-4-hydroxynaphthalene-2-sulfonic acid, were found to be also valid for some 5-substituted orthanilic acid derivatives. The rate-determining stage in the azo coupling at the 3-position can change upon introduction of strong electron-acceptor substituents capable of interacting with the diazo group. The contribution of the multicenter mechanism of deprotonation of the σ-complex with participation of water molecules was presumed to increase in going to the diazo components having electron-donor substituents.
Sulfonation of arylamines: Part III - Solid state synthesis of 2-amino-5-methylbenzenesulfonic acid
Singh, Gurdip,Kapoor, Inder Pal Singh,Juin, Monica
, p. 369 - 372 (2007/10/03)
p-Ditoluidinium sulfate (p-DTS) has been obtained from p-toluidine on treatment with conc. H2SO4 and characterized by molecular weight determination, elemental, gravimetric and spectral analyses. p-DTS yields 2-amino-5-methylbenzenesulfonic acid via solid state reaction induced by heat. A suitable reaction mechanism has been proposed.
Triphendioxazine dyestuffs
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, (2008/06/13)
The novel triphendioxazine dyestuffs of the formula STR1 in which the substituents R, R', T1, T2, X, Y and n have the meanings given in the description are highly suitable for the dyeing and printing of cellulose-containing or amido-containing material.
Azo pigment compositions and process for their preparation
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, (2008/06/13)
This invention is that of an azo pigment composition containing about 1 to 10 percent by weight of a nonionic alkyl polyglycoside dispersing agent. The polyglycosides useful in the invention have the general formulae: wherein: M is an oxygen, sulfur, nitrogen phosphorous or silicon atom; n is an integer from 8 to 18, preferably 8 to 11 and X represents the number average degree of polymerization having a numerical value from about 1 to about 2. These azo pigment compositions are prepared by conducting the azo pigment coupling reaction in the presence of said alkyl polyglycoside. The resulting pigment exhibit superior application properties in water based ink systems.
The Photochemistry of para-Substituted Phenylsulphamates - Photo-Fries Rearrangements
Lally, John M.,Spillane, William J.
, p. 803 - 807 (2007/10/02)
The photolysis (254 nm) of a series of para-substituted phenylsulphamates, XC6H4NHSO3Na in degassed methanolic solutions has been examined.For 1a and 1b photo-Fries type rearrangements to sulphonic acids and photodegradation to anilines have been observed.The halogenosulphamates 1c-1e do not rearrange but degrade to anilines and are photosolvolysed to p-methoxyphenylsulphamic acid.No notable spectral changes took place during the irradiation of 1f over relatively long period.Substrate concentration studies, radical scavenging and sensitization and quenching experiments on 1b indicate that, as previously found for 1a, its photolysis involves an intramolecular radical mechanism with the participation of two triplet states.
Reactive dyestuffs comprising a triazine moiety and a vinylsulfonyl moiety both being linked by a substituted alkylene bridge member
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, (2008/06/13)
A reactive dye of the formula STR1 in which: F is a radical selected from the group consisting of metal-free or metal-containing monoazo or disazo dyes containing at least one --SO3 H group, anthraquinone dyes, sulfophthalocyanine dyes, formazan dyes, phenazine dyes, oxazine dyes and nitroaryl dyes, R is hydrogen, C1 -C4 alkyl which is unsubstituted or substituted with --COOH or --SO3 H, cyanoethyl, or hydroxyethyl, X is fluorine, chlorine, bromine, --SO3 H, phenylsulfonyl or C1 -C4 -alkylsulfonyl, p is 1 or 2 and A is a radical of the formula STR2 in which: Y is chlorine, bromine, fluorine, --OH, --OSO3 H, --O-acyl, --CN, --COOH, --COO--C1 -C4 -alkyl, --CONH2 or --SO2 --Z, the group designated "alk" is a straight or branched polymethylene radical having 2 to 6 carbon atoms, V is STR3 hydrogen or C1 -C4 -alkyl which is unsubstituted or substituted by C1 -C2 -alkoxy, carboxyl, sulfo, halogen or hydroxy, Z is β-halogenoethyl, vinyl or β-acetoxyethyl, or A is a radical of the formulae STR4 in all of which R' is C1-6 -alkyl or hydrogen, Z is as defined above, o is 0 to 6, and m is 2 to 6.
