- Correlation of the rates of Solvolysis of 2,1-benzoxathiol-3-one-1, 1-dioxide (2-sulfobenzoic acid cyclic anhydride)
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Solvolysis of acyclic mixed carboxylic-sulfonic anhydrides in hydroxylic solvents is known to involve displacement at the carbonyl carbon to produce a carboxylic acid (water as the nucleophile) and/or an ester (alcohol as the nucleophile) plus the anion of the sulfonic acid. Parallel solvolyses of the cyclic mixed anhydride 2-sulfobenzoic anhydride (structurally similar to phthalic anhydride but with one carbonyl group replaced by a sulfonyl group) involve expulsion from the carbonyl carbon of a sulfonate anion that remains attached as an orthosubstituent in the benzoic acid and/or benzoate ester produced. This complicates the choice of a solvent-ionising-power scale for use in an extended Grunwald-Winstein equation treatment. The YOTs scale, previously recommended as a good general purpose scale, is chosen and used in conjunction with the NT solvent nucleophilicity scale. An acceptable correlation is obtained, which is improved when the two solvents rich in the highly ionising 1,1,1,3,3,3-hexafluoro-2-propanol are excluded. As the solvent is varied, the sensitivities to the changes induced in the two scales are low, consistent with an early transition state, but their ratio has a value which is typical for a pathway involving addition-elimination, with addition rate-determining. Earlier reports, supporting aspects of the proposed mechanism, are reviewed.
- Kevill, Dennis N.,Ryu, Zoon Ha
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- Sulfonium ion-promoted traceless Schmidt reaction of alkyl azides
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Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C-H and C-C bonds was accessible to the one-pot substitution reaction.
- Ardiansah, Bayu,Kakiuchi, Kiyomi,Morimoto, Tsumoru,Tanimoto, Hiroki,Tomohiro, Takenori
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supporting information
p. 8738 - 8741
(2021/09/08)
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- Sustainable access to sulfonic acids from halides and thiourea dioxide with air
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A sustainable and mild one-step strategy is explored for the synthesis of aryl and alkyl sulfonic acids using a facile combination of halides and sulfur dioxide surrogates under air. The cheap industrial material thiourea dioxide was employed as an eco-friendly and easy-handling sulfur dioxide surrogate, while air was used as a green oxidant. Both aryl and alkyl sulfonic acids were obtained under transition metal-catalyzed or transition metal-free conditions. Mechanistic studies demonstrated that sulfinate was involved as an intermediate in this transformation. Notably, this protocol has been applied to the late-stage sulfonation of the drugs naproxen, isoxepac and ibuprofen.
- Zhang, Hui,Wang, Ming,Jiang, Xuefeng
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supporting information
p. 8238 - 8242
(2020/12/29)
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- Aryl and alkyl sulfonic acid compounds as well as construction method adopting inorganic sulfur salt and application
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The invention discloses aryl and alkyl sulfonic acid compounds as shown in a formula (1) and a synthesis method thereof. The method comprises the following step: aromatic iodine and an inorganic sulfur source or alkyl bromide and an inorganic sulfur source as reaction raw materials react in a solvent under the action of alkali, a catalyst or an additive to obtain a series of aryl and alkyl sulfonic acid compounds. According to the method, the aryl and alkyl sulfonic acid compounds are constructed in one step by taking an inorganic sulfur reagent as a sulfur source, so that the defect of the mode in which the aryl and alkyl sulfonic acid compounds are synthesized by taking concentrated sulfuric acid, chlorosulfonic acid or sulfur dioxide gas and the like as sulfonating reagents in the priorart is avoided. The aryl and alkyl sulfonic acid compounds developed by the invention can be used for synthesizing aryl and alkyl sulfonic acid drug analogues.
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Paragraph 0046-0049; 0088-0091
(2020/09/16)
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- Arylphosphonylation and arylazidation of activated alkenes
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Two radical-mediated processes of activated alkenes, namely arylphosphonylation and arylazidation, are described. The difunctionalization of alkenes by a tandem process that involves radical addition, 1,4-aryl migration, and desulfonylation generates α-ar
- Kong, Wangqing,Merino, Estibaliz,Nevado, Cristina
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supporting information
p. 5078 - 5082
(2014/05/20)
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- Hydrazines and azides via the metal-catalyzed hydrohydrazination and hydroazidation of olefins
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The discovery, study, and implementation of the Co- and Mn-catalyzed hydrohydrazination and hydroazidation reactions of olefins are reported. These reactions are equivalent to direct hydroaminations of C-C double bonds with protected hydrazines or hydrazoic acid but are based on a different concept in which the H and the N atoms come from two different reagents, a silane and an oxidizing nitrogen source (azodicarboxylate or sulfonyl azide). The hydrohydrazination reaction using di-tert-butyl azodicarboxylate is characterized by its ease of use, large functional group tolerance, and broad scope, including mono-, di-, tri-, and tetrasubstituted olefins. Key to the development of the hydroazidation reaction was the use of sulfonyl azides as nitrogen sources and the activating effect of tert-butyl hydroperoxide. The reaction was found to be efficient for the functionalization of mono-, di-, and trisubstituted olefins, and only a few functional groups are not tolerated. The alkyl azides obtained are versatile intermediates and can be transformed to the free amines or triazoles without isolation of the azides. Preliminary mechanistic investigations suggest a rate-limiting hydrocobaltation of the alkene, followed by an amination reaction. Radical intermediates cannot be ruled out and may be involved.
- Waser, Jerome,Gaspar, Boris,Nambu, Hisanori,Carreira, Erick M.
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p. 11693 - 11712
(2007/10/03)
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- Isoxazole intermediate compounds
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A process for the synthesis of N-aryl-3,4-dihydro-2-alkyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides by treatment of N-aryl-N'-alkyl-N'-(2'-alkoxycarbonylbenzenesulfonyl)glycineamides, useful intermediates for said process, with an alkali or al
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