The synthesis and physical evaluation of 5-alkoxy-1,3-thiazoles prepared via Lawesson's reagent-mediated cyclisation of α-benzamido esters

Abstract

The synthesis of the first series of 5-alkoxy-1,3-thiazole-based liquid crystals is reported. The aforementioned liquid crystals were synthesised through a Lawesson's reagent-mediated cyclisation of appropriate α-benzamido esters. This methodology was found to be highly efficient, even on a large scale, and the resulting 5-alkoxy-1,3-thiazoles could be purified without the use of column chromatography. The synthesis and mesomorphic properties of a family of 5-alkoxy-2-(4-cyanophenyl)-1,3-thiazole liquid crystals prepared via this approach are discussed and compared with their thiophene and phenyl analogues.

Keywords:

• 1,3-thiazole
• α-benzamido carbonyl
• cyclisation

Acknowledgements

Financial support for this work through a Research Challenge Grant from the Ohio Board of Regents, and from Kent State University, is gratefully acknowledged. In addition we would like to thank Dr Mahinda Gangoda for assistance in obtaining some of the NMR spectra and Dr Robert J. Twieg for use of his DSC instrument.