Synthesis and study of 4‐(4′‐n‐alkoxybenzoyloxybenzoyl)‐4′′‐n‐butoxyanilides

Abstract

Thirteen compounds with ester and amide linkages were synthesized and their mesogenic properties evaluated. Methyl to n‐propyl derivatives exhibit nematic phases, n‐butyl to n‐decyl derivatives exhibit smectic and nematic mesophases, whereas n‐dodecyl to n‐octadecyl derivatives exhibit only smectic phases. All the smectic homologues exhibit smectic C phases. Middle members of the homologous series exhibit polymorphism of smectic mesophase. A plot of transition temperatures versus number of carbon atoms in the alkoxy chain reveals an odd–even effect for nematic–isotropic transition temperatures. Nematic–isotropic and smectic–cholesteric thermal stabilities of the prepared compounds (series I) are higher compared to those of previously reported compounds, series A, B and C. The results indicate that a simple reversal of a central linkage has a dramatic effect on the appearance of smectic mesophase in a homologous series. The structures of the synthesized compounds were characterized using elemental analysis, thin‐layer chromatography and spectral data.

Acknowledgements

We are indebted to Professor S. G. Devi , Head, Chemistry Department, Faculty of Science for taking interest in the work and providing necessary facilities. We extend our sincere thanks to the Head, Applied Chemistry Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara for providing research facilities. We are thankful to Dr. Jigar Desai, Sr. Scientist, Cadila Pharmaceutical Industries Limited, Ahmedabad, for NMR and mass spectral analysis. We are also thankful to the late Dr. S.S. Madhave Rao and to Mr. S.L. Patel for various analyses.