First observation of Chapman rearrangement of a pseudosaccharyl ether in the so...

• Author(s): Almeida, R. ; Gómez-Zavaglia, Andrea ; Kaczor, A. ; Cristiano, M. L. S. ; Eusébio, M. E. S. ; Maria, T. M. R. ; Fausto, R.
• Date: 2008
• Persistent ID: http://hdl.handle.net/10316/5023
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Pseudosaccharin; 3-(Methoxy)-1,2-benzisothiazole 1,1-dioxide; Chapman rearrangement; DFT calculations; Infrared spectroscopy; Thermomicroscopy
• Document Type: Article
• Language: English

Description

3-(Methoxy)-1,2-benzisothiazole 1,1-dioxide, a pseudosaccharyl ether, was long ago known to undergo a thermal Chapman-like [1,3']-isomerization to the corresponding N-methyl pseudosaccharin at temperatures above its melting point (ca. 184 °C) [Hettler H., Tetrahedron Lett. 1968, 15, 1793]. In the present study, it is shown that this rearrangement can also take place in the solid state, at temperatures as low as 150 °C. This was the first observation of a Chapman-like [1,3']-isomerization in pseudosaccharyl ethers in the solid state. The study has been carried out by a multidisciplinary approach using temperature dependent infrared spectroscopy, differential scanning calorimetry (DSC), and polarized light thermomicroscopy, complemented by theoretical methods. http://www.sciencedirect.com/science/article/B6THR-4RSJDPJ-2/1/0f2df98480df370da897cdccab34054a