3-Arylisoxazolyl-5-carboxylic acid and 5-(Hydroxymethyl)-3-aryl-2-isoxazoline as molecular platforms for liquid-crystalline materials

Journal of the Brazilian Chemical Society

Aline Tavares²  Paolo R. Livotto²  Paulo F. B. Gonçalves¹  Aloir A. Merlo² 

[1] ,Universidade Federal do Rio Grande do Sul Instituto de Química Porto Alegre RS ,Brazil

关键词: 3;    5-disubstituted isoxazolines;    [3+2] 1;    3-dipolar cycloaddition;    liquid crystals;    molecular platform;   

DOI  :  10.1590/S0103-50532009000900025

来源: SciELO

【 摘 要 】

The synthesis of the molecular platform for liquid-crystalline materials based on 3-arylisoxazolyl-5-carboxylic acid (1) and 5-(hydroxymethyl)-3-aryl-2-isoxazoline (2) is described. The key intermediates 1 and 2 are obtained by [3+2] 1,3-dipolar cycloaddition reaction between an arylnitrile oxide and an acrylic acid and allylic alcohol as the dipolarophile. The liquid crystals (LC) compounds are synthesized through a "molecular elongation strategy" from the initial isoxazolinic core by connecting the arylacetylene moiety obtained from the Sonogashira reaction. Under these conditions, the series of liquid crystals 5a-c, 6, 7a-g and 8a-d have been successfully synthesized in fair to good yields. The final compounds display nematic and smectic liquid-crystalline properties. The structural properties of the series of the liquid crystals has been studied using DFT methods at level B3LYP/6-31G(d,p). The equilibrium geometries in the gas phase are presented and analyzed.

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