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Síntese de cristais líquidos derivados dos heterociclos oxazol e tetrazol

by dos Santos, Daniela Rubia

Abstract (Summary)
This work describes the synthesis, the characterization and the study of the mesomorphic properties of two new homologous series of derived compounds of 4-[5-(2-n-alkyltetrazolyl)]-phenyl-3-carboxy-5´-(4?-octylphenyl)-isoxazole ( Series I ) and 4-[5-(2-n-alkylltetrazolyl)]-phenyl-5-benzoyloxy-3-(4-octyloxyphenyl)-1,2,4-oxadiazole (Series II). The synthetic methodology used was efficient, where 4- cyanophenol was used as starting material for thepreparation of the tetrazoles and 1,2,4-oxadiazoles precursors. The isoxazoles intermediates were synthesized departing from the 4-hydroxyacetophenone, through Williamson´s etherification, condensation,cyclization and hydrolysis reactions, obtaining the isoxazole acid. In order to obtain liquid crystals an esterification between the tetrazoles and isoxazoles precursors ( series I) and the 1,2,4-oxadiazoles and tetrazoles precursors ( series II ) wascarried out. All the synthesized compounds have shown mesomorphic properties of enantiotropic smectic C and nematic types for composites of series I, and enantiotropicsmectic C, smectic A and nematic for the series II. In order to characterize the obtained compounds the following techniques were used: IR spectroscopy, 1H NMR, 13C NMR,elemental analysis and optical microscopy of polarized light
This document abstract is also available in Portuguese.
Bibliographical Information:

Advisor:Hugo Alejandro Gallardo Olmedo; Flávia Aparecida Fernandes da Rosa; Paulo César de Jesus; Iêda Maria Begnini

School:Universidade Regional de Blumenau

School Location:Brazil

Source Type:Master's Thesis

Keywords:liquid crystals organic synthesis pentagonal heterocycles

ISBN:

Date of Publication:12/15/2006

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