Liquid Crystals Containing the Isoxazole and Tetrazole Heterocycles

Silva, Luciano da; Gallardo, Hugo; Magnago, Rachel Faverzani; Begnini, Iêda Maria

doi:10.1080/154214090892528

Cited by 22 publications

(14 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…16 In the liquid crystals eld there are a few reports about the synthesis of tetrazoles and their LC properties. [17][18][19] Our synthetic efforts have showed that the tetrazole ring can be used as an alternative building block to prepare a new and more anisotropic class of LCs such as biaxial nematic or ferroelectric smectic C mesophases. The aim of our present work is to report…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of some novel tetrazole liquid crystals

et al. 2013

View full text Add to dashboard Cite

The synthesis and characterization of new 4-[(2-alkyl)-2H-tetrazol-5-yl]phenyl 4-alkyloxybenzoates (5a-i) and 5-{4-[(4-substituted)benzyloxy]phenyl}-2-alkyl-2H-tetrazoles (7a-e) are reported. The reported tetrazoles contain two alkyl chains (six to ten carbon atoms) except for 5h and 7e which have a chiral citronellyl group linked at the N-2 nitrogen atom of the tetrazole ring and 5i having a bromine atom at the para position of benzoate. The regiochemistry in the alkylation step was established unequivocally by single-crystal X-ray analysis for 5a and 5f. The regioselectivity in the alkylation step was also confirmed by analysis of 13 C NMR chemical shifts of the C 5 carbon atom in the tetrazole ring and the methylene carbon atom vicinal to the nitrogen atom. The mesogenic behavior of the liquid crystals was characterized by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. The tetrazolyl benzoates 5a-h show a nematic mesophase. The lengthening of alkyl chains favors the appearance of the smectic mesophase. For instance, 5g displayed nematic and smectic C mesophases, while 5h which has the chiral citronellyl group displayed nematic and smectic A mesophases. Tetrazoles 7a-e did not show mesomorphic behavior mainly due to replacement of the carbonyl by a methylene group.

show abstract

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of some novel tetrazole liquid crystals

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Compound 5 was obtained as reported in the literature. 12 In the following reaction, esterification reaction took place between the phenol (4) and acid chloride (5) in order to result in Series I compounds (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

“…The texture and transition temperatures for compounds were observed by optical microscopy using an Olympus BX 50 polarizing microscope in conjunction with a Mettler FP 82 heating stage. 12 A suspension of 0.042 mol of 4-hydroxybenzonitrile, 11.015 g (0.170 mol) of sodium azide, and 9.012 g (0.170 mol) of ammonium chloride in 28 ml of dimethylformamide was stirred for 11h at 150 o C. After cooling, the reaction mixture was poured into 100 ml of iced water, and the formed solid was isolated by suction filtration and washed with iced water. Purification by recrystallization in water gave an orange solid, yield 79.0%, mp 238.0-238.8ºC.…”

Section: Methodsmentioning

confidence: 99%

“…Purification by recrystallization in water gave an orange solid, yield 79.0%, mp 238.0-238.8ºC. 12 To a 3M solution of sodium hydroxide (26.7 ml) was added 5-(4-hydroxyphenyl)tetrazole (1) (5.385 g, 0.033 mol) under magnetic stirring. Ice and acetic anhydride (0.084 mol) were then added and the mixture was stirred vigorously for 10 to 15 min, forming a precipitate that was isolated by filtration, washed with cold water and recrystallized in water; yield 78.0% and mp 186.3-187.4 o C. IR (KBr, cm -1 ) ν max : 1756, 1612, 1504, 1440, 1364, 1282, 1206.…”

Section: Methodsmentioning

confidence: 99%

“…12 General procedure for synthesis of the homologous series I 4-[5-(2-n-Alkyltetrazolyl)]phenyl-3-carboxy-5'-(4'-octyloxyphenyl)isoxazole (6). 5-(4-Hydroxyphenyl)-2-n-alkyltetrazoles (4) (1.54 mmol) were added in previously distilled pyridine.…”

Section: -(4-hydroxyphenyl)-2-dodecyltetrazole (4d)mentioning

confidence: 99%

See 2 more Smart Citations

Synthesis of liquid crystals derived from oxadiazole, isoxazole and tetrazole heterocycles

Santos¹,

Oliveira²,

Coelho³

et al. 2009

Arkivoc

View full text Add to dashboard Cite

The synthesis is described of new liquid crystalline heteroaromatic compounds containing the five-membered isoxazole, tetrazole and 1,2,4-oxadiazole rings. Two liquid crystalline series including five-membered heterocycles were synthesized. The compounds with the mesogenic units tetrazole and isoxazole (Series I) showed nematic and smectic C phases, while the compounds with the units tetrazole and 1,2,4-oxadiazole (Series II) presented nematic (N), smectic C (Sm C ), and smectic A (Sm A ) mesophases. The transition temperatures and textures of the mesophases determined were characterized using polarized optical microscopy.

show abstract

Pendant triazole ring assisted mesogen containing side chain liquid crystalline polymethacrylates: Synthesis and characterization

2011

View full text Add to dashboard Cite

Two series of click chemistry assisted alkoxymethyl-1H-[1,2,3]-triazol-1-yl containing sidechain liquid-crystalline polymethacrylates were synthesized by free radical polymerization technique. Mesogen was linked to backbone through various spacer units. Monomers and polymers were characterized by FT-IR, 1 H and 13 C-NMR spectral techniques. Thermal stability of polymers was confirmed by thermogravimetric analysis. Mesomorphic property and phase transition temperature of polymers were analysed by differential scanning calorimetry and polarized optical microscopy. Phase transition temperature and mesomorphic property of polymers with respect to insertion of polar alkoxy group on terminal triazole ring and spacer length between backbone and mesogen were investigated. Polymers exhibited grainy like textures under polarized optical microscopy. Spacer length between mesogen and backbone alters phase transition temperature of the polymers.

show abstract

Liquid Crystals Containing the Isoxazole and Tetrazole Heterocycles

Cited by 22 publications

References 13 publications

Synthesis and characterization of some novel tetrazole liquid crystals

Synthesis and characterization of some novel tetrazole liquid crystals

Synthesis of liquid crystals derived from oxadiazole, isoxazole and tetrazole heterocycles

Pendant triazole ring assisted mesogen containing side chain liquid crystalline polymethacrylates: Synthesis and characterization

Contact Info

Product

Resources

About