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Investigations into the Mechanism of Solvolysis of 3-aryloxybenzisothiazoles

2014-12Journal article Open access
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dc.contributor.authorIsmael, Amin
dc.contributor.authorGago, David J. P.
dc.contributor.authorCabral, Lília
dc.contributor.authorFausto, Rui
dc.contributor.authorCristiano, Maria De Lurdes
dc.date.accessioned2018-12-07T14:52:48Z
dc.date.available2018-12-07T14:52:48Z
dc.date.issued2014-12
dc.description.abstractThe solvolysis of selected 3-aryloxybenzisothiazoles (6a-c; Figure 1) in alcohols has been theoretically investigated. The geometries of ethers 6a-c were fully optimized at the DFT(O3LYP) level, with the 6-31++G(d,p) and 6-311++G(3df,3pd) basis sets. Calculations including solvation effects were performed with the 6-31++G(d,p) basis set. Overall, theoretical values for bond lengths and angles around the central ether linkage in ethers 6a-c are very close, for the isolated molecule and in methanol, and are also very close to those obtained by X-ray crystallography, revealing that the nature of the substituent on the aryl system has a negligible effect on geometric parameters around the ether linkage. The same applies to charge distributions, predicted using the NPA approach. However, measured rate constants for the solvolysis of the same compounds in alcohols show that the rate is affected by the electron-withdrawing/-donating characteristics of the substituent on the aryl ring and by the polarity of solvent. Two general pathways were considered for the solvolysis of ethers 6: associative (addition-elimination) or dissociative (fragmentation-recombination) mechanisms. Molecular orbital calculations by means of polarized continuum model (PCM) reaction field predicted that solvolysis of ethers 6 prefers an addition-elimination mechanism. Calculations show also that a dissociative mechanism for the solvolysis of ethers 6a-c is energetically much more demanding than its addition-elimination counterpart and is therefore a highly improbable pathway for the solvolysis. In addition, it was found that the putative cation intermediate formed during a dissociative process should easily convert into its 2-cyanobenzenesulfone cation isomer, via cleavage of the S-N bond.
dc.description.sponsorshipFundação para a Ciência e a Tecnologia, Portugal [PEst-C/MAR/LA0015/2013, PTDC/QUI-QUI/111879/2009]; QREN-COMPETE-UE; CCMAR; FCT [Pest-OE/QUI/UI0313/2014, PRAXIS XXI/BD/19973/99, SFRH/BD/90435/2012]
dc.description.versioninfo:eu-repo/semantics/publishedVersion
dc.identifier.doi10.5562/cca2478
dc.identifier.issn0011-1643
dc.identifier.issn1334-417X
dc.identifier.urihttp://hdl.handle.net/10400.1/11213
dc.language.isoeng
dc.peerreviewedyes
dc.publisherCroatian Chemical Society
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectMetal assisted reactions
dc.subjectMolecular orbital methods
dc.subjectHuman leukocyte elastase
dc.subjectGaussian basis sets
dc.subjectEther bond lengths
dc.subjectMatrix isolation
dc.subjectTransfer hydrogenolysis
dc.subject1,1-Dioxide
dc.subjectReactivity
dc.subjectInhibitors
dc.titleInvestigations into the Mechanism of Solvolysis of 3-aryloxybenzisothiazoles
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage373
oaire.citation.issue4
oaire.citation.startPage363
oaire.citation.titleCroatica Chemica Acta
oaire.citation.volume87
person.familyNameIsmael
person.familyNameCabral
person.familyNameCristiano
person.givenNameAmin
person.givenNameLília
person.givenNameMaria de Lurdes
person.identifier.ciencia-id3510-24A8-36B6
person.identifier.ciencia-idE411-6006-5A01
person.identifier.orcid0000-0002-7346-5998
person.identifier.orcid0000-0001-9362-8128
person.identifier.orcid0000-0002-9447-2855
person.identifier.ridA-8153-2013
person.identifier.ridM-4279-2013
person.identifier.ridG-2345-2012
person.identifier.scopus-author-id35203489500
person.identifier.scopus-author-id9238724800
rcaap.rightsopenAccess
rcaap.typearticle
relation.isAuthorOfPublicationfa01ef7f-7a2a-4f74-a405-714360b862f3
relation.isAuthorOfPublication175a6aa3-9993-480b-9663-ed083a17eedf
relation.isAuthorOfPublicationb16751a6-748e-44b0-9c59-058cbd5b2cc3
relation.isAuthorOfPublication.latestForDiscovery175a6aa3-9993-480b-9663-ed083a17eedf

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