Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/4227
Título: The thermal sigmatropic isomerization of pseudosaccharyl crotyl ether
Autor: Cabral, L. I. L.
Maria, T. M. R.
Martelo, L.
Eusébio, M. E. S.
Cristiano, Maria Lurdes Santos
Fausto, R.
Palavras-chave: Saccharin
3-(E)-(But-2-enoxy)-1,2-benzisothiazole
1,1-dioxide
Sigmatropic rearrangement
Infrared spectroscopy
DSC
Thermomicroscopy
Data: 2013
Editora: Elsevier
Citação: Cabral, L.I.L.; Maria, T.M.R.; Martelo, L.; Eusébio, M.E.S.; Cristiano, M.L.S.; Fausto, R. The thermal sigmatropic isomerization of pseudosaccharyl crotyl ether, Tetrahedron, 69, 2, 810-815, 2013.
Resumo: The thermally induced sigmatropic isomerization of the pseudosaccharyl crotyl ether, 3-(E)-but-2-enoxy)-1,2-benzisothiazole 1,1-dioxide (CBID), has been investigated by using temperature dependent infrared spectroscopy, differential scanning calorimetry (DSC), and polarized light thermomicroscopy. The reaction can take place in both melted and crystalline phases, affording the product resulting from the [3,30] migration of the allylic system from O to N, 2-(E)-1-methylprop-2-en-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (CBIOD). In the melt, the activation energy of the process was determined as being 49.1 5.3 kJ mol 1, with k¼(22.2 0.6) 104 s 1 at 140 C. In the solid state, at 110 C, the rate constant drops by one order of magnitude [k¼(1.46 0.07) 104 s 1]. The enthalpy of reaction, determined by DSC, is DrxH¼ 27.0 0.8 kJ mol 1. Assignments were proposed for the infrared spectra of the observed neat condensed phases of the two compounds.
Peer review: yes
URI: http://hdl.handle.net/10400.1/4227
DOI: http://dx.doi.org/10.1016/j.tet.2012.10.100
ISSN: 0040-4020
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