The thermal sigmatropic isomerization of pseudosaccharyl crotyl ether

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Cabral, LIL (Author) Other; Maria, TMR (Author) Other; Martelo, L (Author) Other; Eusebio, MES (Author) Other; Cristiano, MLS (Author) Other; Fausto, R (Author) Other

Journal

Title: Tetrahedron

Vol. 69

Pages: 810-815

ISSN: 0040-4020

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-002-190

DOI: 10.1016/j.tet.2012.10.100

Abstract (EN): 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 [3,3'] 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 k=(22.2 +/- 0.6)x10(4) s(-1) at 140 degrees C. In the solid state, at 110 degrees C, the rate constant drops by one order of magnitude [k=(1.46 +/- 0.07)x10(4) s(-1)]. The enthalpy of reaction, determined by DSC, is Delta H-rx=-27.0 +/- 0.8 kJ mol(-1). Assignments were proposed for the infrared spectra of the observed neat condensed phases of the two compounds.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6