Synthesis, molecular and crystal structure of spirocyclopropyl derivatives of lupane series and their ability to induce cholesteric mesophase in nematic solvents

Abstract

New spirocyclopropyl derivatives of lupane series were synthesised and their spatial structure was determined by X-ray analysis. These compounds may be used as chiral dopants for cholesteric liquid-crystal compositions which are applied in the surface stabilized cholesteric texture and polymer stabilized cholesteric texture displays with low power consumption. The relationship between stereostructure of the synthesised substances and their ability to induce cholesteric mesophase in different nematic solvents were examined. The highest values of the helical twisting power |β| (213,8 ± 1,1) and (230,5 ± 4,3) mkm-1mol⋅pats-1 in the 4′-pentyl-1,1′-biphenyl-4-carbоnitrile as a nematic solvent were showed by the (1S,2S)-1-(1-phenyl-3-(4-tolyl)-1H-pyrazole-4-yl)-2,2′-spirocyclopropylallobetulone and (1S,2S)-1-(3-(4-methoxyphenyl)-1-phenyl-1H-pyrazole-4-yl)-2,2′-spirocyclopropylallobetulone correspondingly.