- Palladium-Catalyzed ortho-Benzoylation of Sulfonamides through C?H Activation: Expedient Synthesis of Cyclic N-Sulfonyl Ketimines
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The ortho-carbonylation of sulfonylarenes by non-hazardous aryl aldehydes as a carbonyl precursor was reported. In this method, the sulfonamide group serves as a directing group for C?H activation in the presence of a Pd catalyst under ligand-free conditions. The scope of this strategy has been extended to the one-pot two-step synthesis of cyclic N-sulfonyl ketimines under mild reaction conditions. Our approach could be considered as an alternative by circumventing the use of highly reactive organolithium or Grignard reagents to access a wide range of biologically potent cyclic N-sulfonyl ketimines. (Figure presented.).
- Ojha, Subhadra,Panda, Niranjan
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p. 561 - 571
(2019/12/24)
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- A general iodine-mediated synthesis of primary sulfonamides from thiols and aqueous ammonia
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A general and efficient methodology for preparing primary sulfonamides has been developed. In the presence of iodine as the catalyst and TBHP (70% in water) as the oxidant, a wide range of primary sulfonamides were prepared from the corresponding thiols and aqueous ammonia in moderate to good yields.
- Feng, Jian-Bo,Wu, Xiao-Feng
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supporting information
p. 6951 - 6954
(2016/07/30)
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- PYRAZOLYL ACYLSULFONAMIDE DERIVATIVES AS ENDOTHELIN CONVERTING ENZYME INHIBITORS AND USEFUL IN THE TREATMENT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE
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The invention provides compounds of formula (I),wherein R?1?,R?2? ,R?3? and R?4? are as defined in the specification,processes for preparing such compounds,to pharmaceutical compositions comprising such compounds and to the use of the compounds as active
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Page/Page column 62-63
(2008/06/13)
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- Kinetics and mechanism of oxidation of D-fructose and D-glucose by sodium salts of N-(chloro)-mono/di-substituted benzenesulfonamides in aqueous alkaline medium
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In an effort to introduce N-chloroarylsulfonamides of different oxidizing strengths, nine sodium salts of mono- and di-substituted N- chloroarylsulfonamides are employed as oxidants for studying the kinetics of oxidation of D-fructose and D-glucose in aqueous alkaline medium. The results are analyzed along with those by the sodium salts of N-chlorobenzenesulfonamide and N-chloro-4-methylbenzenesulfonamide. The reactions show first-order kinetics each in [oxidant], [Fru/Glu], and [OH-]. The rates slightly increase with increase in ionic strength of the medium. Further, the rate of oxidation of fructose is higher by 4 to 5 times than that of the glucose oxidation, by the same oxidant. Similarly, Ea values for glucose oxidations are higher by about 1.5 times the Ea values for fructose oxidations. The results have been explained by a plausible mechanism, and the related rate law deduced. The significant changes in the kinetics and thermodynamic data are observed with change of substituent in the benzene ring. It is because Cl + is the effective oxidizing species in the reactions of N-chloroarylsulfonamides. The oxidative strengths of the latter therefore depend on the ease with which Cl+ is released from them. The ease with which Cl+ is released from N-chloroarylsulfonamides depends on the electron density of the nitrogen atom of the sulfonamide group, which in turn depends on the nature of the substituent in the benzene ring. The following Hammett equations are valid for the oxidation of fructose and glucose, log kobs = -3.13 + 0.54 σ ρ and log kobs = -3.81 + 0.28 σ ρ, respectively. The enthalpies and entropies of activations for oxidations by all the N-chloroarylsulfonamides correlate well with isokinetic temperatures of 301 K and 299 K, for fructose and glucose oxidations, respectively. The effect of substitution in the oxidants on the Ea and log A for the oxidations is also considered.
- Gowda, B. Thimme,Damodara,Jyothi
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p. 572 - 582
(2007/10/03)
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- A mild, efficient method for the synthesis of aromatic and aliphatic sulfonamides
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A two-step method was developed for the synthesis of aromatic and aliphatic sulfonamides from the corresponding sulfinates using bis(2,2,2-trichloroethyl)azodicarboxylate as the electrophilic nitrogen source. The intermediate sulfonylhydrazides were obtained in very good yields and were cleaved under reductive conditions to deliver the desired sulfonamides. A variety of substituents in the aromatic ring are well tolerated as well as heterocycles.
- Chan, Wing Yan,Berthelette, Carl
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p. 4537 - 4540
(2007/10/03)
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- DISSOCIATION OF SUBSTITUTED BENZENESULPHONAMIDES IN WATER, METHANOL AND ETHANOL
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Thirteen monosubstituted arylsulphonamides (XC6H4SO2NH2) and two 3,4-disubstituted arylsulphonamides (X2C6H3SO2NH2) have been synthetized and their dissociation constants have been measured by potentiometric titration in water, methanol, and ethanol.The Hammett substitution dependences have been calculated for all the media, and changes in the reaction constants due to transition from water to alcohols are discussed in confrontation with analogous dependences of benzoic acids.The reaction constant ρ found in methanol is lower than that in water.The dissociation constants have been treated by the method of the principal components and by multiple linear regression.
- Ludwig, Miroslav,Pytela, Oldrich,Kalfus, Karel,Vecera, Miroslav
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p. 1182 - 1192
(2007/10/02)
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