- Cornforth and Corey-Suggs reagents as efficient catalysts for sulfonation of aromatic and heteroaromatic compounds using NaHSO3 under solvent free and microwave conditions
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Cornforth and Corey-Suggs reagents Pyridinium Dichromate (PDC) and Pyridinium Chlorochromate (PCC) were explored as efficient catalysts for sulfonation of aromatic and heteroaromatic compounds using NaHSO3 in aqueous acetonitrile medium at room temperature within 1–4 h, while microwave assisted reactions took place within 1–4 min under solvent-free conditions. These observations indicate significant rate accelerations in microwave assisted reactions. which were explained due to the bulk activation of molecules induced by insitu generated high temperatures and pressures when microwaves are transmitted through reaction medium.
- Fatima, Touheeth,Duguta, Govardhan,Purugula, Venkanna,Yelike, Hemanth Sriram,Kamatala, Chinna Rajanna
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p. 1001 - 1006
(2020/07/27)
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- Regioselective Sulfonation of Aromatic Compounds over 1,3-Disulfonic Acid Imidazolium Chloride under Aqueous Media
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1,3-Disulfonic acid imidazolium chloride ([Dsim]Cl), as a Bronsted acidic ionic liquid, is introduced for the sulfonation of aromatic compounds by in situ generation of sulfuric acid at 50 °C under mild conditions and in aqueous medium.
- Moosavi-Zare, Ahmad Reza,Zolfigol, Mohammad Ali,Noroozizadeh, Ehsan
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p. 1682 - 1684
(2016/07/06)
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- Divergent C-H functionalizations directed by sulfonamide pharmacophores: Late-stage diversification as a tool for drug discovery
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Modern drug discovery is contingent on identifying lead compounds and rapidly synthesizing analogues. The use of a common pharmacophore to direct multiple and divergent C-H functionalizations of lead compounds is a particularly attractive approach. Herein, we demonstrate the viability of late-stage diversification through the divergent C-H functionalization of sulfonamides, an important class of pharmacophores found in nearly 200 drugs currently on the market, including the non-steroidal anti-inflammatory blockbuster drug celecoxib. We developed a set of six categorically different sulfonamide C-H functionalization reactions (olefination, arylation, alkylation, halogenation, carboxylation, and carbonylation), each representing a distinct handle for further diversification to reach a large number of analogues. We then performed late-stage, site-selective diversification of a sulfonamide drug candidate containing multiple potentially reactive C-H bonds to synthesize directly novel celecoxib analogues as potential cyclooxygenase-II (COX-2)-specific inhibitors. Together with other recently developed practical directing groups, such as CONHOMe and CONHC6F5, sulfonamide directing groups demonstrate that the auxiliary approach established in asymmetric catalysis can be equally effective in developing broadly useful C-H activation reactions.
- Dai, Hui-Xiong,Stepan, Antonia F.,Plummer, Mark S.,Zhang, Yang-Hui,Yu, Jin-Quan
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p. 7222 - 7228
(2011/06/26)
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- A novel method for sulfonation of aromatic rings with silica sulfuric acid
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Direct and chemoselective sulfonation of aromatic compounds with silica sulfuric acid in 1,2-dichloeoethane or under solvent-free conditions.
- Hajipour, Abdol R.,Mirjalili, Bi Bi F.,Zarei, Amin,Khazdooz, Leila,Ruoho
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p. 6607 - 6609
(2007/10/03)
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- Reactivity of sterically hindered aromatic sulfonic acid derivatives: VII.* hydrolysis of arenesulfonyl chlorides in aqueous acetonitrile
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Hydrolysis of sterically hindered arenesulfonyl chlorides in aqueous acetonitrile is accelerated by both electron-acceptor and some electron-donor substituents in the benzene ring. A multifactor kinetic model of the process is proposed. 1998 MAHK Hayka/Interperiodica Publishing.
- Rubleva,Krut'ko,Mitchenko
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p. 1006 - 1009
(2007/10/03)
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- REACTIVITY OF STERICALLY HINDERED DERIVATIVES OF AROMATIC SULFONIC ACIDS. I. EFFECT OF SUBSTITUENTS ON RATE AND MECHANISM OF HYDROLYSIS OF SOME SUBSTITUTED BENZENESULFONYL CHLORIDES
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The kinetics of the hydrolysis of substituted benzenesulfonyl chlorides XArSO2Cl in 70percent aqueous dioxane at 303, 313, and 323 K were studied by acid-base titration.The effect of the investigated set of substituents cannot be described by a single linear relationship of the Hammett type.The substrates containing methyl groups at the ortho positions of the aromatic ring exhibit enhanced reactivity.The effect of the structural changes in the sulfonyl chlorides on the nature of bond formation and cleavage in the transition state is discussed in terms of the SN2 mechanism.An attempt is made to explain the V-shaped form of the relationship between log k and ? from the standpoint of the hyperconjugation effect, the contribution from which amounts to about 10percent of the ρ value.
- Vizgert, R. V.,Rubleva, L. I.,Maksimenko, N. N.
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p. 727 - 730
(2007/10/02)
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- KINETICS AND MECHANISM OF HYDROLYSIS OF AROMATIC SULFONYL CHLORIDES IN AQUEOUS SULFURIC ACID SOLUTIONS
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The kinetics of the hydrolysis of 12 aromatic sulfonyl chlorides were studied by a spectrophotometric method in water and aqueous sulfuric acid solutions ( 1.0 - 60.5 wt.percent ) at 25 deg C and in 50percent sulfuric acid at several temperatures.It was shown that the reaction obeys the single-parameter equation log keff = log k0 + m'X, in which keff and k0 are the first-order rate constants in a solution with "excess acidity" X and in water respectively.The coefficient m' depends on the substituent in the ring and is equal to -0.85 to -0.38.The activity of the water does not enter into the equation for the calculation of keff.For the hydrolysis of nine substituted sulfonyl chlorides in 50percent sulfuric acid a satisfactory correlation is observed between log keff and the Σ?0.Palm induction constants ( ρ = -1.85 +/- 0.12 ).A reaction mechanism is proposed in which the rate-determining stage in the hydrolysis of the ArSO2Cl is the transformation of the complex H2O...SO2(Cl)Ar, in the form of which all the sulfonyl chloride dissolved in the water is present, into the reaction products.
- Gnedin, B. G.,Ivanov, S. N.,Shchukina, M. V.
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p. 731 - 737
(2007/10/02)
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- Mass Spectral Studies of Alkylbenzenesulphonic Acids Through Their S-Benzylisothiouronium Salts
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The mass spectra of alkylbenzenesulphonic acids in the form of their S-benzylisothiouronium salts have been studied.These S-benzylisothiouronium salts dissociated into two parent reactant ions: (i) alkylbenzenesulphonic acid and (ii) S-benzylisothiourea.The characteristic fragmentation patterns of alkylbenzenesulphonic acids (0-5 substituted alkyls) were studied and compared with those of the parent ion peak hydrocarbons.The intensity of the molecular decreased with the increase in the molecular weight of the sulphonic acids.Desulphonation as well as loss of the alkyl group was observed in all the spectra.Migration of the alkyl group from S to 0, followed by degradation, was also observed in all the spectra studied.
- Borthakur, Arun,Rao, V. S. Bhaskar
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- Sulfosilylation of Aromatic Hydrocarbons by Trimethylsilyl Chlorosulfonate
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Aromatic hydrocarbons 2 ,6 ,8 ,9 ,13 ,16 ,18 ,19 ,22 react with trimethylsilyl chlorosulfonate (1) to give trimethylsilyl arenesulfonates 5, 7, 11, 12, 15, 23 or sulfonic acids 17, 20, 21.If trimethylsilyl sulfonates are obtained, working up of the sulfonation mixtures is possible by distillation.By hydrohalogenolysis of trimethylsilyl sulfonates 5 at 0-5 deg C anhydrous sulfonic acids 3 result.The pathways to diphenylsulfone (25a) in the reaction of benzene (2a) with 1 were investigated.In this connection we succeeded in synthesizing benzenepyrosulfonic acid (28) and trimethylsilyl benzenepyrosulfonate (29).
- Hofmann, Karin,Simchen, Gerhard
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p. 282 - 297
(2007/10/02)
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