15872-50-1Relevant articles and documents
Preparation and evaluation of some novel liquid crystals as antioxidants
Ashmawy,Nessim,Elnaggar,Osman
, p. 188 - 198 (2017)
Four liquid crystal compounds of the form 2-sec-butyl-4-[(4-X-phenyl) diazenyl) phenyl-4-(octadecyloxy] benzoate symbolized as I18a, I18b, I18c, and I18d were prepared in which the substituent (X) was taken CHs
Synthesis and mesomorphic properties of bis ester derivatives of coumarin containing chalcone linkage
Shah, Priyanka,Soni, Rina,Soman, Shubhangi S
, (2021/05/04)
Bis ester derivatives of coumarin containing chalcone linkage with various terminal alkoxy groups were designed, synthesized and characterized. Compounds 11a-m were studied for their mesomorphic properties using polarizing optical microscope & differential scanning calorimetry and photophysical properties using UV-vis & fluorescence spectroscopy. In this particular homologous series, compounds having lower flexible alkoxy chains showed very good mesogenic property with nematic mesophase formation, while analogues with higher chains failed to show any liquid crystalline property. Compound 11a with methoxy group showed very good absorbance and fluorescence as compared to higher chain length analogues.
Synthesis, mesomorphic properties and biological evolution of calamitic-shaped chalcone-based LCs: effect of lateral and terminal group
Dwivedi, Durgesh J.,Thakor, Akshay,Desai, Vipul,Sharma, Vinay S.,Patel
, p. 16 - 32 (2021/05/26)
The mesomorphic properties of linear shaped homologous series based on two linkage group have been designed and synthesized with different side chain substituents (-OR) on the one end of terminal side with presence of lateral nitro group and second terminal iodo substituted group. Novel series consists thirteen members (C1 to C8, C10, C12, C14, C16, C18). Compounds (C1 to C6) showed nonliquid crystalline properties while compound (C7 to C18) displayed smectic and nematogenic mesophase properties. The textures of smectic C and nematic phase are fan, schlieren and droplets type. All these compounds were characterized by spectroscopic techniques such as [FTIR] and 1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compounds were observed by POM and further confirmed by DSC and XRD. Chalconyl ester based compounds (C3 to C12) shows good antibacterial as well as antifungal activity compared with corresponding standard drugs.
Synthesis and characterization of novel rod-like ester-based liquid crystalline homologous series: Effect of tert-butyl tail on mesomorphism
Thakur, Shavi,Patel, Hemant N.
, p. 76 - 89 (2021/04/14)
A new rod-like homologous series consisting twelve compounds with central ester linkage and terminal tert-butyl group, tert-butyl [4-(4’-n-alkoxybenzoyloxy)benzoates] has been synthesized and characterized through standard spectroscopic techniques like UV, FT-IR, 1HNMR, DSC, POM, and XRD. Methoxy and ethoxy derivatives are nonmesogenic. Nematic mesophase commences as enantiotropy from propyloxy derivative and persists up to the octadecyloxy derivatives. Smectic A mesophase commences as monotropy from propyloxy to the octadecyloxy derivatives. The mesomorphic properties of present series are compared with other structurally related series to evaluate the effect of terminal tert-butyl group on mesomorphism. Two derivatives are subjected to in?vitro antimicrobial activity.
Controlling the formation of heliconical smectic phases by molecular design of achiral bent-core molecules
Alaasar, Mohamed,Cai, Xiaoqian,Eremin, Alexey,Kurachkina, Marharyta,Lehmann, Anne,Liu, Feng,Nagaraj, Mamatha,Poppe, Marco,Poppe, Silvio,Tamba, Maria-Gabriela,Tschierske, Carsten,Vij, Jagdish K.
supporting information, p. 3316 - 3336 (2020/03/23)
Fluids with spontaneous helical structures formed by achiral low molecular mass molecules is a newly emerging field with great application potential. Here, we explore the chemical mechanisms of the helix formation by systematically modifying the structure of a bent 4-cyanoresorcinol unit functionalized with two different phenyl benzoate based aromatic rods and terminated with two alkyl chains of variable length. The majority of these achiral compounds self-assemble, forming a short-pitch heliconical liquid crystalline phase in broad temperature ranges. In some cases, it occurs without any competing low-temperature phase. We demonstrate that the mirror symmetry broken mesophase occurs at the paraelectric-(anti)ferroelectric transition if the tilt angle of the molecules in the smectic layers is around 18-20° and if this transition coincides with a change of the tilt correlation between the layers. In the close vicinity of this transition, a field-induced heliconical phase develops as well as a new heliconical phase with polarization-randomized structure. These investigations provide a blueprint for the future design of achiral molecules capable of spontaneous mirror symmetry breaking by the formation of heliconical liquid crystalline phases.
“Effect of the linking unit on the calamitic-shaped liquid crystal: a comparative study of two homologous series of benzoate and cinnamate linked compounds”
Kashyap, Dinesh,Patel, Sunil,Prajapat, Varsha,Sharma, Vinay,Vasava, Dilip
, p. 58 - 70 (2019/08/28)
Two homologous series based on three linking groups have been synthesized and well characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by using optical polarized microscopy (POM) and confirmed by differential scanning calorimetry (DSC) analysis. In this present investigation, we have synthesized two homologous series viz. (E)-4-(3-(4-(tetra decanoyloxy) phenyl) acryloyl) phenyl-4-n-alkoxy benzoate (Series-1) and 4-((E)-3-(4-(((E)-3-(4-n-alkoxy phenyl) acryloyl) oxy) phenyl)-3-oxo prop-1-en-1-yl) phenyl tetradecanoate (Series-2). Both of the series are differing with respect to the first linking group. All the homologous in following series displays LC properties on heating as well as cooling condition except first four homologous (C1 to C4) in series-1 and six homologous (C1 to C6) in series-2. To get more insights, the HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens.
“Synthesis, Mesomorphic and DFT Studies of Chalcone Derived Room Temperature Liquid Crystal with Presence of Lateral Nitro and N, N-Dimethyl Amino Terminal Group”
Shukla, Devendra K.,Sharma, Vinay S.,Prajapat, Varsha,Patel
, p. 8 - 26 (2019/10/14)
In this present article, we wish to report on the liquid-crystalline properties of chalcone-ester based homologous series of compounds having aliphatic chain length in n-alkoxy group (n = 1 to 10, 12, 14, 16, 18). The present series consisted thirteen compounds, in which comp.C1 and C2 shows nonliquid crystalline properties, while comp.C3 to C7 display SmC phase and comp.C8 to C18 exhibits only nematic phase. Textural pattern of presently synthesized compounds are schlieren and threaded type. All this compounds were well characterized by elemental analysis, FT-IR and 1H NMR. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC). Detailed XRD investigation endorses the presence of the nematic phase in higher homologues and SmC phase in lower homologues. It is shown that chalcone with ester as linking unit favors a calamitic liquid crystalline behaviour in molecules. To get more insights, the DFT based HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens. Chalconyl ester based compounds C3 to C12 shows antibacterial as well as antifungal activity compared with corresponding standard drugs.
Preparation, structure and optical properties of thermochromic liquid crystal compounds containing (?)-menthyl with selective reflection
Luo, Cong-Cong,Wang, Xin-Jiao,Han, Lu-Juan,Jia, Ying-Gang,Ying, Shao-Ming,Wang, Ji-Wei
, p. 241 - 250 (2018/11/27)
A series of new chiral liquid crystal compounds named MOPnB containing (?)-menthyl group has been prepared and characterized by FT-IR and 1H NMR spectra. The thermal properties and optical textures were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Increasing the length of the terminal alkoxy group tended to decrease the clearing points and narrow the temperature range of the N* phase as well as favored the development of SmC* phase. Furthermore, Bragg selective reflection spectra of the compounds were measured by ultraviolet/visible spectrometer (UV/Vis). All compounds MOPnB (n = 2, 4, 6, 8, 10) revealed the thermochromic property or selective reflection of visible light in the N* phase. Additionally, only MOP10B and MOP12B in the SmC* phase had the thermochromic phenomena and gave red-saffron colour.
BRARTEMICIN ANALOGUES
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Page/Page column 50; 51; 65, (2019/05/22)
The invention relates to brartemicin analogues of Formula (IV) and their uses. These compounds are potent Mincle agonists and Th1-stimulating vaccine adjuvants.
Lipidated Brartemicin Analogues Are Potent Th1-Stimulating Vaccine Adjuvants
Foster, Amy J.,Nagata, Masahiro,Lu, Xiuyuan,Lynch, Amy T.,Omahdi, Zakaria,Ishikawa, Eri,Yamasaki, Sho,Timmer, Mattie S. M.,Stocker, Bridget L.
, p. 1045 - 1060 (2018/02/17)
Effective Th1-stimulating vaccine adjuvants typically activate antigen presenting cells (APCs) through pattern recognition receptors (PRRs). Macrophage inducible C-type lectin (Mincle) is a PRR expressed on APCs and has been identified as a target for Th1-stimulating adjuvants. Herein, we report on the synthesis and adjuvanticity of rationally designed brartemicin analogues containing long-chain lipids and demonstrate that they are potent Mincle agonists that activate APCs to produce inflammatory cytokines in a Mincle-dependent fashion. Mincle binding, however, does not directly correlate to a functional immune response. Mutation studies indicated that the aromatic residue of lead compound 9a has an important interaction with Mincle Arg183. In vivo assessment of 9a highlighted the capability of this analogue to augment the Th1 response to a model vaccine antigen. Taken together, our results show that lipophilic brartemicin analogues are potent Mincle agonists and that 9a has superior in vivo adjuvant activity compared to TDB.
