Synthesis of maleo- and citraconopimaric acid derivatives with mesogenic groups as chiral dopants to LC-compositions

The method for maleopimaric acid aminoamides synthesis has been developed, which involves the treatment of maleopimaric acid with an excess of thionyl chloride at 18-20 °С and the subsequent reaction of the obtained maleopimaric acid chloride and aromatic diamines (1,4-diaminobenzene, 4,4’-diaminodiphenyl) in 80.5-94.3 % yields. The reaction of maleopimaric acid aminoamides with aliphatic and aromatic aldehydes (isovalerianic aldehyde, benzaldehyde, 4-methoxy-benzaldehyde, 4-chlorobenzaldehyde) gave maleopimaric acid azomethines containing mesogenic groups (4-biphenyl, 4-phe-nylaminobezilidene) in 56.5-99.3 % yields. Maleopimaric and citraconopimaric acid 4-biphenylamides were first synthesized by the reaction of acid chlorides of these acids and 4-aminobiphenyl in yields of 91.3-94.8 %. It was established that the obtained substances are optically active and the specific rotation ([α]D) of the synthesized compounds is -45.0° ÷ -118.2°. It has been shown that the chiral LC phase is formed once the obtained additives (amides and azomethines of maleopimaric acid) are introduced into the nematic liquid crystal matrix (MLC 6809-000, Merck). The helical twisting power of the studied compounds reaches 12.4 pm^-1. The data obtained can be applied in the development of new industrial chiral LC compositions for use in the electronic and LC industry, e.g. TN LCD fabrication.

1. Kitzerow H.-S., Bahr C. (eds.) Chirality in Liquid Crystals. New York, Springer-Verlag, 2001. 501 p.

2. Li Q., Green L., Venkataraman N., Shiyanovskaya I., Khan A., Urbas A., Doane J.W. Reversible Photoswitchable Axially Chiral Dopants with High Helical Twisting Power. Journal of the American Chemical Society, 2007, vol. 129, no. 43, pp. 12908-12909. https://doi.org/10.1021/ja0747573

3. Bei M. P., Yuvchenko A. P., Muravskii Al. An., Muravskii An. Al. New Amides and Imidoamides of Maleopimaric Acid as a Chiral Dopants for Nematic Liquid Crystal Compositions. Russian Journal of Organic Chemistry, 2018, vol. 88, no. 2, pp. 251-256. https://doi.org/10.1134/S107036321802010X

4. Muravskii Al. An., Bei M. P., Muravskii An. Al., Yuvchenko A. P., Danilovich S. V., Kozak G. V., Agabekov V. E. Chiral liquid crystal mixture. Patent Republic of Belarus no. 21021. Publ. date 30 April 2017 (in Russian).

5. Panda H. Handbook on Oleoresin and Pine Chemicals. Asia Pacific Business Press, 2008. 608 p.

6. Schuller W. H., Lawrence R. V. Reaction products of diamines and the monoacid chloride of maleopimaric acid. Patent USA, no. 3503998. Publ. date 31 May 1970.

7. Coates J. Interpretation of Infrared Spectra, A Practical Approach. Myers R. A. (ed.) Encyclopedia of Analytical Chemistry. John Wiley & Sons Ltd, Chichester, 2000, pp. 10815-10837. https://doi.org/10.1002/9780470027318.a5606_

8. Tomilin M. G., Nevskaya G. E. Liquid Crystal Displays. Saint-Petersburg, St.-Petersburg State University ITMO, 2010. 108 p. (in Russian).

9. Schuller W. H., Lawrence R. V. Some new derivatives of maleopimaric acid. Journal of Chemical and Engineering data, 1967, vol. 12, no. 2, pp. 267-269. https://doi.org/10.1021/je60033a030

10. Koroleva E. V., Gusak K. N., Ignatovich Zh. V., Ermolinskaya A. L., Bei M. P., Yuvchenko A. P. Synthesis of maleopimaric and citraconopimaric acids N-[3-(pyrimidin-2-yl)aryl]amides. Russian Journal of Organic Chemistry, 2012, vol. 48, no. 8, pp. 1121-1125. https://doi.org/10.1134/S1070428012080143