3-(<i>E</i>)-But-2-enoxy-1,2-benzisothiazole 1,1-Dioxide: Unusual C—O—C Ether Bond Lengths and Reactivity

Barkley, James V.; Cristiano, Maria Lurdes Santos; Johnstone, R. A. W.; Loureiro, Rui M. S.

doi:10.1107/s0108270196014151

Cited by 13 publications

(19 citation statements)

References 9 publications

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“…When the compounds are heated neat or in solution, this bond may then be broken, while the C HAR -O bond becomes a double bond, affording the corresponding N-allyl-or N-alkylbenzisothiazolones through Cope-or Chapman-like isomerizations, respectively. [14][15][16][17][18] The thermal isomerization of 3-methoxy-1,2-benzisothiazole 1,1-dioxide has been addressed recently. 17 It was shown that its Chapman-type conversion into 2-methylbenzisothiazol-3-one 1,1-dioxide occurs in the melted phase and also in the crystalline phase.…”

Section: Introductionmentioning

confidence: 99%

Thermally Induced Sigmatropic Isomerization of Pseudosaccharyl Allylic Ether

et al. 2009

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The thermally induced sigmatropic isomerization of the pseudosaccharyl allylic ether [3-(allyloxy)-1,2-benzisothiazole 1,1-dioxide; ABID] has been investigated by a multidisciplinary approach using temperature dependent infrared spectroscopy, differential scanning calorimetry, and polarized light thermomicroscopy, complemented by theoretical methods. Migration of the allylic system from O to N occurs in the melted ABID, and the thermally obtained 2-allyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (ABIOD) starts to be produced at ca. 150 °C, in a process with an activation energy of ∼92 kJ mol−1. From kinetic data, a concerted [3,3′] sigmatropic mechanism is proposed. In the temperature range investigated, ABIOD was found to exhibit polymorphism. Cooling of the molten compound leads to the production of a metastable crystalline form, which upon annealing at room temperature might be transformed to the stable crystalline phase. ABID shows a single crystalline variety. Assignments were proposed for the infrared spectra of the observed neat condensed phases of the two compounds.

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Section: Introductionmentioning

confidence: 99%

Thermally Induced Sigmatropic Isomerization of Pseudosaccharyl Allylic Ether

et al. 2009

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“…Apart from the wide commercial applications of saccharin itself, its derivatives receive an increased attention as they show herbicidal [1,2], antimicrobial and antifungal activity [3][4][5] or potential in enzymatic inhibition [6]. Additionally, substituted 1,2-benzisothiazole 1,1-dioxides (pseudosaccharins) are important intermediates in the organic synthesis, as their O-ethers provide efficient intermediates for reductive cleavage of the CAO bond in phenols [7,8], benzylic [9] and naphthylmethylic alcohols [10], through heterogeneous catalytic transfer hydrogenolysis, or through cross-coupling with organometalic reagents [11][12][13]. Though substituent is an additional requirement, ensuring a proper alignment of the compound on a catalyst surface (alkylpseudosaccharyl ethers are unreactive) [8], the structural basis of the enhanced reactivity of this kind of pseudosaccharyl ethers towards transition metal-catalyzed ipso-replacement lies in the unusual bond lengths and geometry of their C R AOAC A linkage (where R = heteroaromatic ring and A = aliphatic or aryl group) [8][9][10][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Molecular structure and infrared spectra of the monomeric 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (methyl pseudosaccharyl ether)

Kaczor

Almeida

Gómez‐Zavaglia

et al. 2008

Journal of Molecular Structure

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The computational description of saccharin (1,2-benzisothiazol-3(2H)-one-1,1-dioxide) and its derivatives is difficult due to the presence of hypervalent S@O bonds in their structures. Therefore, in this investigation, the HF, DFT/B3LYP and MP2 methods were used to predict the geometry and the infrared spectrum of the saccharyl derivative 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (MBID). Their relative predictive capabilities were then evaluated by comparing the obtained results with experimentally available data, namely the newly obtained IR spectra of MBID isolated in low-temperature inert matrices. For each method, different basis sets [6-31++G(d,p), 6-31++G(3df,3pd), 6-311++G(d,p), 6-311++G(2df,2pd), 6-311++G(3df,3pd), aug-cc-pVDZ and aug-cc-pVTZ] were considered. The best overall agreement has been achieved at the B3LYP/6-311++G(3df,3pd) and B3LYP/6-31++G(3df,3pd) levels of theory, showing the adequacy of the B3LYP functional to describe the investigated properties in this type of compounds and stressing the relevance of including high-order polarization functions in the basis set.The chosen level of theory 3pd)] was applied to analyze the vibrational spectra and the geometry of the title molecule. In agreement with the experiment, the CAOAC linkage in MBID is predicted by these calculations to exhibit considerably short (1.320 Å ) and long (1.442 Å ) (N@)CAO and (H 3 )CAO bonds, respectively, and a hybridization of the central oxygen atom close to sp 2 (the CAOAC angle is predicted to be ca. 117°). This CAOAC bonding pattern fits the well-known high reactivity of MBID upon thermal rearrangement, which has been shown to result in easy selective [1,3 0 ]-isomerization of the compound.

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“…3-Propenyloxy-1,2-benzisothiazole 1,1-dioxide was obtained through reaction of the allylic alcohol prop-2-en-1-ol, with 3-chloro-1,2-benzisothiazole 1,1-dioxide, using a synthetic methodology described elsewhere [16].…”

Section: Infrared Spectroscopymentioning

confidence: 99%

“…Therefore, the originally strong C A -O bond in the hydroxylic compound becomes weak, and the bond between the oxygen and the carbon of the heteroaromatic ring (C AR -O) becomes very strong [15]. In allyl-and alkylpseudosaccharyl ethers, the net result of the electronic changes is also important, in that it provides a molecular structure that lies close to a transition state structure, in which the originally strong C A -O bond in the ether becomes easily cleavable to give the ther-mally isomerised N-allyl or N-alkyl isomers, 2-allyl-or 2-alkyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxides (benzisothiazolones), respectively, through Claisen-or Chapman-like rearrangements [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Conformational and structural analysis of 2-allyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide as probed by matrix-isolation spectroscopy and quantum chemical calculations

Gómez‐Zavaglia

Kaczor

Coelho

et al. 2009

Journal of Molecular Structure

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a b s t r a c t 2-Allyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (ABIOD) has been studied by matrix-isolation infrared spectroscopy and quantum chemical calculations. A conformational search on the B3LYP/6-311++G(3df,3pd) potential energy surface of the molecule demonstrated the existence of three conformers, Sk, Sk 0 and C, with similar energies, differing in the orientation of the allyl group. The calculations predicted the Sk form as the most stable in the gaseous phase, whereas the Sk 0 and C conformers have calculated relative energies of ca. 0.6 and 0.8-3.0 kJ mol À1 , respectively (depending on the level of theory). In agreement with the relatively large (>6 kJ mol À1 ) calculated barriers for conformational interconversion, the three conformers could be efficiently trapped in an argon matrix at 10 K, the experimental infrared spectrum of the as-deposited matrix fitting well the simulated spectrum built from the calculated spectra for individual conformers scaled by their predicted populations at the temperature of the vapour of the compound prior to matrix deposition. Upon annealing the matrix at 24 K, however, both Sk and Sk 0 conformers were found to convert to the more polar C conformer, indicating that this latter form becomes the most stable ABIOD conformer in the argon matrix.

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3-(E)-But-2-enoxy-1,2-benzisothiazole 1,1-Dioxide: Unusual C—O—C Ether Bond Lengths and Reactivity

Cited by 13 publications

References 9 publications

Thermally Induced Sigmatropic Isomerization of Pseudosaccharyl Allylic Ether

Thermally Induced Sigmatropic Isomerization of Pseudosaccharyl Allylic Ether

Molecular structure and infrared spectra of the monomeric 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (methyl pseudosaccharyl ether)

Conformational and structural analysis of 2-allyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide as probed by matrix-isolation spectroscopy and quantum chemical calculations

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