- 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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- Preparation process of ethylbenzenesulfonamide
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The invention discloses a preparation process of ethylbenzenesulfonamide. Ethyl benzene and chlorosulfonic acid serve as main raw materials, p-ethylbenzenesulfonyl chloride is prepared under the effect of a catalyst in the appropriate temperature and an appropriate solvent, and the P-ethylbenzenesulfonyl chloride and ammonium hydroxide directly react to generate the high-purity ethylbenzenesulfonamide. According to steps involved in a reaction, operation and separation are easy, the yield is high, the production route is concise, and the preparation process meets the needs of industrial production.
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Paragraph 0021-0026
(2019/03/28)
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- B-Alkyl Suzuki-Miyaura cross-coupling of tri-n-alkylboranes with arylbromides bearing acidic functions under mild non-aqueous conditions
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An efficient and chemoselective Pd-catalyzed B-alkyl Suzuki-Miyaura cross-coupling of tri-n-alkylboranes with arylbromides possessing acidic functions is described. This protocol features the relatively weak base Cs2CO3 and mild non-
- Sun, Hui-Xia,Sun, Zhi-Hua,Wang, Bing
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experimental part
p. 1596 - 1599
(2009/06/18)
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- Direct B-alkyl Suzuki-Miyaura cross-coupling of trialkyl-boranes with aryl bromides in the presence of unmasked acidic or basic functions and base-labile protections under mild non-aqueous conditions
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An efficient and chemoselective palladium-catalyzed direct B-alkyl Suzuki-Miyaura cross-coupling of trialkylboranes with diversely functionalized aryl bromides is described. A wide variety of unmasked acidic or basic functions are tolerated. The mild non-
- Wang, Bing,Sun, Hui-Xia,Sun, Zhi-Hua,Lin, Guo-Qiang
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experimental part
p. 415 - 422
(2009/10/23)
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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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- Investigation of structure-activity relationships in a series of glibenclamide analogues
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In this study, the synthesis of 15 new glibenclamide analogues is described. The conformational trends of these analogues were investigated using Monte Carlo conformational analysis. The conformational analysis results resolved the discrepancy between previous molecular modelling simulations of glibenclamide and allowed rationalizing the effect of aqueous environment on the overall conformation. The 3D-QSAR study was carried out with respect to the compounds' ability to antagonize the [3H]-glibenclamide binging in rat cerebral cortex. Superimposition of the antagonists was performed using the conformations derived from atom-by-atom fit to the glibenclamide crystal structure and this alignment was used to develop CoMFA models. CoMFA provided a good predictability: number of PLS components = 2, q2 = 0.876, R 2 = 0.921, SEE = 0.455 and F = 70. Best CoMFA models showed the steric and lipophilic properties as the major interacting forces whilst the electrostatic property contribution was a minor factor.
- Yuriev, Elizabeth,Kong, David C.M.,Iskander, Magdy N.
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p. 835 - 847
(2007/10/03)
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- Determination of absolute configuration of a metabolite (-)- hydroxyhexamide from acetohexamide, syntheses of (-)- and (+)- hydroxyhexamides and (-)- and (+)-acetoxyhexamides
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Enantioselective acetylation of (±)-4-(1- hydroxyethyl)benzenesulfonamide 6 with 'Acylase I' (No. A 2156) from Aspergillus melleus in the presence of vinyl acetate gave (R)-4-(1- acetoxyethyl)benzenesulfonamide 7 (98% ee) and (S)-6 (98% ee). Both (S)-6 and (R)-7 were individually converted to the (S)-hydroxyhexamide 2 (>99% ee) and (R)-hydroxyhexamide 2 (>99% ee), respectively. The absolute configuration of a metabolite (-)-hydroxyhexamide 2 from acetohexamide 1 was found to be S based on unequivocal chemical methods including X-ray analysis.
- Akita, Hiroyuki,Kurashima, Katsumi,Nozawa, Masako,Yamamura, Shigeo,Seri, Kenzi,Imamura, Yorishige
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p. 4331 - 4340
(2007/10/03)
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- UNE VOIE ORIGINALE ET SELECTIVE DE FONCTIONNALISATION EN POSITION META DU FLUORO- ET DE L'ETHYLBENZENE
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An original and regioselective method for the meta functionalisation of fluoro- and ethylbenze is reported.This process involves a 2,5-disilylation of these subtrates using trimethylchlorosilane in the presence of lithium in THF as the solvent.After aromatisation, monodesilylation in position 2- and electrophilic substitution of the trimethylsilyl group in position 5-, meta acetyl-, senecioyl-, benzoyl-, and iodofluorobenzenes and ethylbenzenes as well as the sodium salts of metafluoro or meta ethylbenzenesulfonic acid and 3-aminosulfonylfluorobenzene were obtained in good yields. pair of diastereomeric triamines 15 and 16.A tricyclic diazasystem 19 was formed from the reaction of cyanide with the carbamoylated chloroenamine 18.Monochloroenamine 10a and dichloroenamine 12a showed a significant mutagenic behaviour in the Ames test.
- Bennetau, Bernhard,Krempp, Michele,Dunogues, Jacques,Ratton, Serge
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p. 8131 - 8142
(2007/10/02)
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- Process for the production of benzenesulfonamides
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Process comprises the combination of two steps of interacting a R-benzene, sulfuric acid and phosphorus oxychloride to obtain 4-R-benzenesulfonyl chloride and amidating said sulfonyl chloride to produce 4-R-benzenesulfonamide.
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- THERMAL Z,E-ISOMERIZATION OF IMINES. VI. N-ARYLSULFONYLIMINES OF ACETONE AND 2,6-DI-tert-BUTYL-1,4-BENZOQUINONE
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The thermal topomerization of acetone N-arylsulfonylimines and 2,6-di-tert-butyl-1,4-benzoquinone N-arylsulfonyl-4-monoimines was studied by the dynamic PMR method.The inversion mechanism of the topomerization of the N-arylsulfonylimines was established on the basis of an investigation into the electronic and steric effects of substituents at the sulfur atom on the sizes of the barriers to topomerization.The effect of nN-3dS and nN-?c-s* interactions and the induction effect of the arylsulfonyl group on the sizes of the barriers to inversion at the nitrogen atom are considered.The reduction of the barriers to inversion in the N-arylsulfonylimines with increase in the electron-withdrawing characteristics of the para substituents in the aryl ring is largely determined by the increase in the nN-3dS interaction.
- Prosyanik, A.V.,Kol'tsov, N.Yu.,Romanchenko, V.A.,Belov, V.V.,Burmistrov, K.S.,Loban', S.V.
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p. 335 - 342
(2007/10/02)
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