- Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
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A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
- Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
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supporting information
p. 18591 - 18598
(2021/06/28)
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- Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
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The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
- Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
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supporting information
p. 2157 - 2161
(2021/05/21)
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- Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
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Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
- Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
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p. 3344 - 3350
(2021/07/26)
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- 1,3-Oxazine-2-one derived dual-targeted molecules against replicating and non-replicating forms of Mycobacterium tuberculosis
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The high mortality rate and increasing prevalence of resistant Mtb are the major concerns for the Tuberculosis (TB) treatment in this century. To curtail the prevalence of resistant Mtb, we have prepared 1,3-oxazine-2-one based dual targeted molecules. Compound 67 and 68 were found to be equally active against replicating and non-replicatiing form of Mtb (MICMABA 3.48 and 2.97 μg/ml; MICLORA 2.94 and 2.15 μg/ml respectively). They had found to suppress the biosynthesis of alfa, methoxy and keto-mycolate completely, as well as inhibit enzymatic activity of MenG (IC50 = 9.11 and 6.25 μg/ml respectively for H37Ra; IC50 = 11.76 and 10.88 μg/ml respectively for M smegmatis).
- Velappan, Anand Babu,Kesamsetty, Dhanunjaya,Datta, Dhrubajyoti,Ma, Rui,Hari, Natarajan,Franzblau, Scott G.,Debnath, Joy
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supporting information
(2020/10/02)
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- Synthesis and mesomorphic properties of coumarin derivatives with chalcone and imine linkages
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We report here design and synthesis of two new mesogenic homologous series of coumarin derivatives consisting of chalcone and imine central linkages along with terminal n-alkoxy chain. All the compounds were synthesized and characterized by combination of elemental analysis and standard spectroscopic methods. All compounds were screened under polarising optical microscope (POM) for liquid crystalline properties, thermogram of all compounds were studied using differential scanning calorimetry (DSC) to get phase transition temperatures, enthalpy and entropy. X-ray single crystal study of n-octyloxy coumarin derivative 16 g was resolved with imine central linkage, which showed linear rod like geometry.
- Durgapal, Sunil Dutt,Soni, Rina,Soman, Shubhangi S.,Prajapati
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- Anticancer, antimicrobial activities of quinoline based hydrazone analogues: Synthesis, characterization and molecular docking
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Based on the biologically active heterocycle quinoline, a series (18a-p) of quinoline hydrazone analogues were prepared, starting from 6-bromo/6-chloro-2-methyl-quinolin-4-yl-hydrazines. For all the newly synthesized compounds cytotoxic activities were carried out at the National Cancer Institute (NCI), USA, against full NCI 60 human cancer cell lines. Amongst all the tested compounds, nine compounds (18b, 18d, 18e, 18f, 18g, 18h, 18i, 18j, 18l) exhibited important anti-proliferative activity at 10 μM concentration and were further screened at 10-fold dilutions of five different concentrations (0.01, 0.1, 1, 10 and 100 μM) with GI50 values ranging from 0.33 to 4.87 μM and LC50 values ranging from 4.67 μM to >100j μM. Further, the mean values of GI50, TGI and LC50 of the most potent compound 18j were compared with the clinically used anticancer agents bendamustine and chlorambucil, revealed that the quinolyl hydrazones holds promise as a potential anticancer agents. Further all the newly prepared compounds were screened for their antimicrobial activity. All the quinolyl hydrazones displayed good to excellent antimicrobial activity with MIC values ranging from 6.25 to 100 μg/mL against the tested pathogenic strains. Molecular docking of the synthesized compounds into the active binding site of human DNA topoisomerase I (htopoI) was carried out to predict the binding mode to the DNA topoisomerase I inhibitors. Hopefully in future, compounds based on quinoline core could be used as a lead compounds for designing new anticancer agents.
- Katariya, Kanubhai D,Shah, Shailesh R.,Reddy, Dushyanth
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supporting information
(2019/11/26)
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- 2-Aryl benzazole derived new class of anti-tubercular compounds: Endowed to eradicate mycobacterium tuberculosis in replicating and non-replicating forms
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The high mortality rate and the increasing prevalence of Mtb resistance are the major concerns for the Tuberculosis (TB) treatment in this century. To counteract the prevalence of Mtb resistance, we have synthesized 2-aryl benzazole based dual targeted molecules. Compound 9m and 9n were found to be equally active against replicating and non-replicating form of Mtb (MIC(MABA) 1.98 and 1.66 μg/ml; MIC(LORA) 2.06 and 1.59 μg/ml respectively). They arrested the cell division (replicating Mtb) by inhibiting the GTPase activity of FtsZ with IC50 values 45 and 64 μM respectively. They were also capable of kill Mtb in non-replicating form by inhibiting the biosynthesis of menaquinone which was substantiated by the MenG inhibition (IC50 = 11.62 and 7.49 μM respectively) followed by the Vit-K2 rescue study and ATP production assay.
- Datta, Dhrubajyoti,Debnath, Joy,Franzblau, Scott G.,Ghosh, Kalyan Sundar,Hari, Natarajan,Ma, Rui,Rana, Shiwani,Velappan, Anand Babu
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- Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
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Aliphatic aldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphatic aldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon less homologous carbonyl compounds, the reduction of the same key intermediates followed by an oxidation produced one-carbon more homologous carbonyl compounds.
- Yoo, Jae Won,Seo, Youngran,Park, Jong Beom,Kim, Young Gyu
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- Biomolecule-derived supported cobalt nanoparticles for hydrogenation of industrial olefins, natural oils and more in water
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Catalytic hydrogenation of olefins using noble metal catalysts or pyrophoric RANEY nickel is of high importance in the chemical industry. From the point of view of green and sustainable chemistry, design and development of Earth-abundant, less toxic, and more environmentally friendly catalysts are highly desirable. Herein, we report the convenient preparation of active cobalt catalysts and their application in hydrogenations of a wide range of terminal and internal carbon-carbon double bonds in water under mild conditions. Catalysts are prepared on multi-gram scale by pyrolysis of cobalt acetate and uracil, guanine, adenine or l-tryptophan. The most active material Co-Ura/C-600 showed good productivity in industrially relevant hydrogenation of diisobutene to isooctane and in natural oil hardening.
- Pews-Davtyan, Anahit,Scharnagl, Florian Korbinian,Hertrich, Maximilian Franz,Kreyenschulte, Carsten,Bartling, Stephan,Lund, Henrik,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 5104 - 5112
(2019/09/30)
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- “Effect of the linking unit on the calamitic-shaped liquid crystal: a comparative study of two homologous series of benzoate and cinnamate linked compounds”
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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.
- Kashyap, Dinesh,Patel, Sunil,Prajapat, Varsha,Sharma, Vinay,Vasava, Dilip
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- Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene) hydrazines
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{1-[4-(n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines (n-alkoxy = O(CH2)nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.
- Awad, Adil A.,Omarali, Al-Ameen Bariz,Al-Karawi, Ahmed Jasim M.,Al-Qaisi, Zyad Hussein J.,Majeed, Samer Ghanim
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- Liquid Crystalline Properties of 4,4'-methylenebis(N-(4-Alkanoxybenzylidene)aniline): Synthesis, Characterization, and Theoretical study
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The paper presents six homologues series of Schiff bases ether compounds distinguished by the length of terminal alkoxy groups which substituted on a side benzene nucleus. The above structures were demonstrated through the use of spectroscopic techniques, like FT- IR and1H-NMR. Polarized hot stage optical microscopy was used to study both mesomorphic properties and phase transitions. The results showed that out of the six compounds only three (B2, B3 and B4) were pure (marble) nematic mesophase, while no liquid crystal properties for (B5, B6 and B7) compounds. The theoretical study for the electronic structures was intended to study the effects of alkyl chain length on the electronic structure by using Gaussian program, DFT and 6-31G as basis set. The theoretical results indicate that there is no effect to the terminal substituted alkoxy groups on the HOMO energies but there is an effect on LUMO energies through decreasing energy for the prepared compounds.
- Yaseen, Mohammed Taha,Kshash, Abdullah Hussein
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p. 1107 - 1114
(2020/01/08)
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- Mesomorphism dependence on central bridge and tail ended polar group
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A novel azoester homologous series of laterally and terminally substituted viz, RO–C6H4–CH=CH–COO–C6H3–(CH3) –N=N–C6H4–Cl is synthesized, characterized and studied with a view to understand and establish the relation between molecular structure and thermotropic liquid crystalline property of its homologs. Series consists of twelve homologs. LC properties commence from very first member of a series and continue up to last homolog as enantiotropic nematic with absence of smectic property even in the monotropic condition. Transition temperatures of homologs were determined by polarizing optical microscopy equipped with a heating stage. The transition curves Cr?N and N?I behaved in normal manner. Thermal stability for nematic is 196.7?C whose mesophaselength ranges from 35°C to 131°C.
- Ranchchh, Avani R.,Chavda, Kavita,Bhanderi, Roshani,Patel, Suman,Bhoya
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- Mesomorphism dependence on molecular rigidity and flexibility
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A novel homologous series of liquid crystalline properties is synthesized and studied with a view to understand the effect of molecular structure on its thermotropic properties. Novel homologous series consisted of thirteen homologs. All the homologs are enantiotropically smectogenic with absence of nematic property even in the monotropic condition. Textures of the homologs as observed through an optical hot stage polarizing microscopy. The mesophase temperature range vary minimum from 6.0°C to a maximum 37.0°C at the methyloxy and propyloxy derivatives of a series respectively with its thermal stability (Sm–I) 127.0°C. Transition curves of a phase diagram behaved in normal manner. Odd–even effect is observed for Sm–I transition curve.
- Ranchchh, Avani R.,Bhoya
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- “Dependence of Mesomorphism in Combination with Fluoro and Chloro Groups”
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A novel azoester homologous series with chloro lateral group and a fluoro terminal end group was synthesized and characterized for mesomorphic properties. It consists of thirteen azo ester derivatives from trans-4-n-alkoxy cinnamic acid with 4-hydroxy-3-chloro phenyl azo-3-chloro-4-fluoro benzene. Mesomorphic property commences from C4homologue as smectic.C1 to C3 member of the series are non-mesomorphic. C4 to C18 homologous are enantiotropic smectic A phase. The nematic mesophase is totally absent. Texture and transition temperatures of the homologues are determined by an optical polarizing microscopy equipped with heating stage. 1H NMR, IR spectra, mass spectra, of some member is included. The spectroscopic analysis supports the molecular structure. A phase diagram is used to illustrate the mesomorphic behaviour across the series. Mesophaselength for smectic is varying from18.0°C to 69.00C. Mesomorphic properties of the novel azoester series are compared with structurally similar series.
- Ranchchh, Avani R.,Tharesha, Bhavna R.,Bhoya
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- Synthesis and Structure–Activity Relationships of Novel Benzylamine-Type Antifungals as Butenafine-Related Antimycotics
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Benzylamine-type antimycotics like naftifine, butenafine, or terbinafine are a well-known class of antimycotics since the 1980s. The following paper describes the synthesis and biological evaluation of a series of novel benzylamine-type antimycotics characterized by an isooctyl side chain and various substituents at the benzylamine moiety. The compounds were prepared from benzaldehyde derivatives and 2-amino-6-methylheptane by reductive amination with sodium triacetoxyborohydride and subsequent precipitation with hydrogen chloride. The antimycotic activity of the resulting compounds was evaluated in an agar diffusion assay against the yeasts C. glabrata and Yarrowia lipolytica, the mold Aspergillus niger and the dermatophyte H. burtonii. The compounds were also tested in a microdilution assay against the yeast Candida glabrata and the dermatophyte H. burtonii to determine the minimal inhibitory concentrations (MIC). Compounds with an aromatic ether side chain or a short alkyl ether side chain showed significant antimycotic activity against C. glabrata, comparable to terbinafine or clotrimazole.
- Krauss, Jürgen,Stadler, Martina,Bracher, Franz
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- Efficient and practical method for the synthesis of hydrophobic azines as liquid crystalline materials
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A series of hydrophobic symmetrical azines: 1,2-bis[4-(n-alkoxy)benzylidene]hydrazine (where, n-alkoxy: O(CH2)nH, n = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, or 18) have been prepared following an efficient and practical method. These compounds have been synthesized via the condensation reaction of hydrazine hydrate and appropriately 4-(n-alkoxy) benzaldehydes in acidic medium under ambient conditions. The prepared organic compounds have been characterized and their structures were elucidated depending upon micro-elemental analysis and spectral data (IR, UV-Vis, 1HNMR, 13C{1H}NMR, 2D 1H-1H-cozy, 2D 1H-13C-HSQC, and mass spectra). Liquid crystalline behavior of the prepared compounds was studied using polarized light optical microscopy and differential scanning calorimetry techniques. This study revealed that all the compounds displayed enantiotropic liquid crystal properties, exhibiting smectic and nematic mesophases.
- Hammood, Ali Jasim,Kased, Ahmed Fadhel H.,Al-Karawi, Ahmed Jasim M.,Raseen, Sameem R.,Tomi, Ivan Hameed R.,Omar Ali, Al-Ameen Bariz
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p. 114 - 129
(2017/07/04)
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- Mesogenic naphthyl derivatives
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Two new mesogenic homologous series of liquid crystalline naphthalene derivatives with different central linkages: 2- Naphthyl-4-n-alkoxybenzoates (I) and trans-2-Naphthyl -4-n –alkoxycinnamates(II), have been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. Twelve compounds have been synthesized in both the series I and II. In series I, methoxy to n-pentyloxy derivatives are non mesogenic, n-hexyloxy to n-hexadecyloxy derivatives exhibit monotropic nematic mesophase. Smectic A mesophase commences from n-decyloxy derivatives as a monotropy and persist up to the last member synthesized. All the 12 compounds of series II exhibit mesomorphism. Methoxy to n-propyloxy derivatives exhibit monotropic nematic mesophse, and n-butyloxy to n-tetradecyloxy derivatives exhibit enantiotropic nematic mesophase. n-Hexayloxy to n-hexadecyloxy derivatives also exhibit enantiotropic smectic A mesophase. The mesomorphic properties of present series were compared with each other and with a structurally related mesogenic homologous series to evaluate the effects of central linkage on mesomorphism.
- Patel,Prajapati
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p. 106 - 115
(2017/03/08)
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- Study the effects of terminal side chain and –nitro group on mesomorphic behaviour of cinnamate-chalconyl based liquid crystal
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The influence of the terminal side chain and lateral nitro on mesomorphism due to the flexibility and polarity of lateral group is investigated. A new homologues series is synthesized to accomplish this aim. The C1 to C3 homologue are nonmesomorphic, while the rest of the homologues exhibit enantiotropic nematic and smectic properties. The texture of the nematic mesophase is of threaded, Schlieren and droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques of FTIR and 1H Nuclear magnetic resonance (NMR). The phase behaviour was studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction techniques.
- Sharma, Vinay S.,Patel
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- Mesomorphic study of novel chalconyl-ester-based nonisomeric series: Synthesis and characterization
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A newly designed homologues series: 3-(3-(4-(Dimethylamino) phenyl) acrylonyl) phenyl 3-(4-n-alkoxyphenyl) acrylate has been synthesized and studied through chalconyl ester linking group at (meta) position. The series consists of 13 compounds, in which C1 to C4 homologue are nonliquid crystal, while C5 to C18 exhibit nematic phase, and C12 to C18 shows smectic and nematic phase with enantiotropically manner. Mesophase image of present compounds are rod like, needle and threaded type textures investigated by POM. All this compounds were characterized by elemental analysis, FT-IR and 1H NMR. The mesomorphism is measured by POM, DSC, and molecular packing is determined by XRD technique. The following synthesized chalconyl ester-based compounds C5 to C12 shows antibacterial as well as antifungal activity compared with corresponding standard drugs. Analytical and spectral data confirmed the molecular structures of homologous series.
- Sharma, Vinay S.,Patel
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- Tuning the mesomorphic properties of nonisomeric chalconyl-ester bases homologous series: The effect of tail group
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The mesomorphic properties of nonlinear chalconyl ester homologous series can be tuned in a predictable fashion with tail groups (-OC16H33) substituents on the terminal side. Novel series consisted thirteen members (C1–C8, C10, C12, C14, C16, C18). C1 to C5 homologues are nonliquid crystal, C6 to C14 homologues shows nematic mesophase enantiotropically, while C16, C18 exhibits smectic as well nematic properties. The texture of the nematic mesophase is of fan shaped, schlieren and nematic droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques such as [FTIR] and 1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compoundswere observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC).
- Sharma, Vinay S.,Patel
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- Synthesis and study of mesomorphic properties in rod-like chalconyl compounds
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In order to investigate the influence of the central linking group and effect on flexibility on mesophase behavior of liquid crystal we have synthesized newly homologous series viz. 3-(4-Octyloxyphenyl)-1-(4′-n-alkoxy phenyl) prop-2-en-1-one (Series-l) consists of thirteen homologues (C1 to C8, C10, C12, C14, C16, C18). Textures of a nematic phases are threaded or Schlieren type. The textures of smectic and nematic phase are directly judged from the heating and cooling condition. Group efficiency order for mesophases is derived on the basis of thermal stabilities from the comparative study of thermometric data determined from structurally analogous series. A transition curve as depicted in a phase diagram behaves in normal manner. Structural and conformational characterization of these new compounds had achieved by 1H NMR, 13C NMR, IR, and elemental analysis.
- Sharma, Vinay S.,Patel
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- Synthesis and mesomorphic properties of new chalconyl-linkage-based liquid crystal compounds: The effect of flexibility
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A new series of liquid crystals involving chalconyl-based mesogenic units interlinked between two benzene cores were designed and synthesized. The target chalconyl compounds were obtained by the reaction of 4-n-alkoxy benzaldehyde with 4-n-hexadecyloxy (–OC16H33) acetophenone in presence of base. The liquid crystalline properties of synthesized compounds were observed by polarizing optical microscope study. The molecular structures of the compounds were confirmed by Fourier transform infrared, 1H, and 13C nuclear magnetic resonance spectra. The compounds of the series C3 to C8, C10, C12, C14, C16, and C18 exhibited mesophase in enantiotropically manner. The transition temperature reduced as alkyl spacer of left side group increased. The observed texture images are droplets, broken fan, and threaded like. Thermal stability of current homologous series for (N-I/I-N) is 69.8°C and for smectic phase (Sm + N) is 58.0°C.
- Sharma, Vinay S.,Patel
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p. 129 - 140
(2017/03/08)
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- Molecular flexibility dependence on mesogenic behaviors of isomeric and nonisomeric series
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A novel homologous series containing vinyl ester and azomethane central bridges and n-alkoxy as well as 3″,4″-dimethyl groups as flexible terminal/lateral groups viz. RO?C6H4?CH = CH?COO?C6H4?N?CH?C6H3-(CH3)2 have been synthesized and studied with a view to establishing the relation between molecular structure and thermotropic liquid crystal (LC) properties with reference to molecular flexibility within the series. The series consists of twelve homologues (C1 to C16). C6 and C7 homologues are smectogenic plus nematogenic and C8 to C16 homologues are only smectogenic, and the rest of the homologues (C1 to C5) are nonmesomorphic. Transition temperatures and the textures of the homologues were determined using an optical polarizing microscope equipped with a heating stage (POM). The textures of a nematic phase are threaded or Schlieren and that of a smectic phase are of the A or C type. Analytical, thermal and spectral data support the molecular structures. Smectic and nematic thermal stabilities are 116.85°C and 147.5°C, respectively. Whose Sm?N/I and N-I mesophase lengths are varied between 15°C to 21°C and 25°C to 62°C, respectively. The novel compounds are compared with structurally-similar series.
- Rakhasia,Ranchchh, Avani R.,Bhoya
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p. 159 - 167
(2017/03/08)
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- Mesomorphism dependence on molecular rigidity and substitution of same functional group on lateral or terminal position of tailed phenyl ring
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Novel liquid crystal materials (LCs) of low temperature range (53°C to 75°C) have been synthesized through a series of chalconyl derivatives consisting of two phenyl rings bonded through a –CH?CH?CO? central bridge to study the effect of molecular structure on LC properties in general and with a focus on molecular rigidity. The novel homologues series (C1 to C18) consists of thirteen homologues with general formula RO?C6H4?CH?CH?CO?C6H4?OC10H21(n) (meta). The C1, C2, C3 homologues are nonliquid crystals (NLC) and the rest of the homologues (C4 to C18) are either monotropic or enantiotropic liquid crystals. C4 to C6 homologues are enantiotropicnematic and the rest of the mesomorphic homologues are (C7 to C18) monotropicsmectic in addition to monotropicnematic character. Transition and melting temperatures including textures of homologues were determined by an optical polarizing (POM) microscopy equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren, and that of the smectic phase are of the type Smectic A or C as judged directly from the heating top of the microscope. Thermal stability for smectic is very poor and of the nematic is (N-I) 69.3°C whose, total mesophase length ranges between 07.0 to 14.0°C at C8 and C4 homologues respectively.
- Sharma, Vinay S.,Patel
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p. 178 - 187
(2017/03/08)
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- The effect of position of octadecyloxy tail on the formation of liquid crystal with chalconyl-ester and chalconyl-vinyl ester series: Comparison with corresponding linkage group
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Two series of chalconyl-based liquid crystals which differ from each other in the position of the first linking group have been synthesized and characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC). We have synthesized two homologous series viz. 3-(3-(4-(Octadecyloxy) phenyl) acrylonyl) phenyl 3-(4-n-alkoxyphenyl) acrylate (series-1) and 3-(3-(4-(Octadecyloxy) phenyl) acryloyl) phenyl 4-n-alkoxy benzoate (series-2). Series-1 has chalconyl-ester central linkage group while in series-2 chalconyl-vinyl ester group is present and tail octadecyloxy side chain is common in both homologous series. All the homologous in present series display LC property in enantiotropical manner except first three homologous in both series.
- Solanki,Sharma, Vinay. S.,Patel
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p. 216 - 232
(2017/03/08)
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- Synthesis, characterization, and mesomorphic investigation of vinyl ester-substituted chalcones and effect of lateral ?NO2 and ?OCH3 group
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A novel homologous series of α-4-(4′-n-alkoxy cinnamoyloxy) phenyl β-2″-nitro, 3″–4″ di methoxy benzoyl ethylenes, H2n + 1CnO?C6H4?CH?CH?COO?C6H4?CO?CH?CH?C6H2(NO2) (OCH3)2 (n = 1–8, 10, 12, 14, 16, 18) has been synthesized. All these compounds have been characterized by suitable spectroscopic techniques. C1 homologue is nonmesogenic, while C2 homologue shows enantiotropic nematogenic property and the rest of the homologous (C3?C18) displayed enantiotropically smectogenic plus nematogenic phase. Phase transition temperatures and textures of the LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. The mesomorphic properties of these compounds were confirmed by differential scanning calorimetry (DSC) analysis.
- Sharma, Vinay S.,Patel
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p. 241 - 251
(2017/03/08)
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- Synthesis and mesomorphic properties of new chalconyl-ester based liquid crystals: The effect of tail group
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A new homologous series viz. 4-(3-(3, 4-dioctadecyloxy) phenyl)-3- oxoprop-1-en-1-yl) phenyl-3-(4-n-alkoxy phenyl) cinnamate) based on two linking groups have been synthesized and characterized. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). All synthesized compounds exhibited LC behaviour except compound C1. Thermal stability of smectic and nematic phase of present series are 79.0°C and 120.0°C whose temperature range is vary from 14 to 20°C and 24 to 56°C respectively. The mesomorphic properties of present series were compared with other structurally related mesogenic homologous series to evaluate the effects of tail group on mesomorphism.
- Sharma, Vinay S.,Vekariya, Rajesh H.,Sharma, Anuj S.,Patel
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- Synthesis and mesomorphic properties of quinoline-8-yl-4-((4-n-alkoxy benzylidene) amino) benzoate: The effect of linkage group
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A new homologous series viz. quinoline-8-yl-4-((4-n-alkoxy benzylidene) amino) benzoate based on two central linking groups have been designed and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and protonmagnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by polarizing optical light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). All synthesized compounds displayed LC property except first two homologue. The lower homologues (n = 4 to 8) display SmA and SmC phase while, in higher homologues (n = 10 to 18) SmC and nematic phasewere seen in heating and cooling condition.
- Sharma, Vinay. S.,Vekariya, Rajesh H.,Sharma, Anuj. S.,Patel
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- Synthetic pathway for a new calamitic series of liquid crystal: Comparison with corresponding linkage group
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Reduction-responsive cystamine-incorporated gelatin microspheres were prepared by an emulsification method. On SEM micrograph, the microsphere, prepared at pH 9.0 and at the carboxyl/amino group molar ratio of 1:1, was sphere-like and its diameter was a few to 100 μm. The gelatin to cystamine ratio of the microsphere was about 1:0.2 (w/w), determined by energy dispersive X-ray spectroscopy. Two endothermic peaks were observed around 92°C and 126°C, which were thought to be the melting point of gelatin-rich phase and that of cystamine-rich phase, respectively. The microsphere released its payload (FITC-dextran) in dithiothreitol (a reducing agent) concentration-dependent manner.
- Sharma, Vinay S.,Vekariya, Rajesh H.,Sharma, Anuj S.,Patel
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p. 143 - 157
(2017/10/27)
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- New hockey stick shaped amino allylidene (?N?CH?CH?CH) based compounds: Effect of linkage group on mesomorphic properties
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Two nonlinear hockey stick shaped homologous series based on three linking groups have been synthesized and characterized by elemental analyses and spectroscopic techniques. The mesomorphic properties of these compounds were observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In this present investigation, we have synthesized two homologous series viz. 2-((3-phenyl allylidene) amino) phenyl 4-((4-n-alkoxy benzylidene) amino) benzoate (series-1) and 4-((2-((3-phenyl allylidene) amino) phenoxy) carbonyl) phenyl-4-n-alkoxy benzoate (series-2). Both the series are differing with respect to first linking group. In series-1, comp.C4-C18 shows nematic as well as smectic phase while in series-2, comp.C10-C16 shows smectic and nematic phase while comp.C4-C18 shows only nematic phase.
- Sharma, Vinay. S.,Vekariya, Rajesh. H.,Sharma, Anuj. S.,Patel
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- The effect of position of tert-butyl tail group on the formation of liquid crystal in Schiff base ester based homologous series
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We report a newly rod like calamatic liquid crystalline materials, which are constructed by the self-organization of a rod-like carboxylic acid derivative based on Schiff base ester as the linking group with tert butyl tail group. A newly series of 4-(tert-butyl) phenyl 4-((4-alkoxybenzylidene) amino) benzoate with different alkyl chain spacer (n = 1 to 8, 10, 12, 14, 16, and 18) were synthesized and their mesomorphic properties were investigated by differential scanning calorimetry and polarized optical microscopy. All homologous in present series displays mesophase in enantiotropically manner. Thermal stability of SmC-SmA is 137.5 °C. All the compounds were characterized by spectroscopic and elemental analysis. The effects of varying left alkyl side spacer on mesomorphism with its structurally related compounds in series have been discussed.
- Sharma,Patel
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- Nano-NiFe2O4 as an efficient catalyst for regio- and chemoselective transfer hydrogenation of olefins/alkynes and dehydrogenation of alcohols under Pd-/Ru-free conditions
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Here, we have demonstrated the magnetic nano-NiFe2O4 catalyzed transfer hydrogenation of olefins/alkynes using isopropyl alcohol as a source of hydrogen under ligand/base/Pd-/Ru-metal-free conditions, and dehydrogenation of alcohols under oxidant-free conditions.
- Payra, Soumen,Saha, Arijit,Banerjee, Subhash
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p. 52495 - 52499
(2016/06/13)
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- Syntheses and characterization of aryl-substituted pyrogallol[4]arenes and resorcin[4]arenes
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Seven aryl-substituted pyrogallol[4]arenes and six aryl-substituted resorcin[4]arenes were synthesized through the acid catalyzed reaction of either pyrogallol or resorcinol with a specific alkoxybenzaldehyde. Single crystal X-ray data was obtained for all thirteen compounds. In order to determine the effect of the different pendent -R groups, four properties were investigated: π-π distance, inward tilt, twist angle, and the angle between the planes containing the pendent -R groups. Positioning of the -R groups, the carbon atom chain length of the -R groups, the number of upper-rim hydroxyl groups (resorcin[4]arene vs. pyrogallol[4]arene), and the number of substituted phenyl groups all influenced these four properties. The trends that develop are investigated and discussed.
- Pfeiffer, Constance R.,Feaster, Kyle A.,Dalgarno, Scott J.,Atwood, Jerry L.
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p. 222 - 229
(2015/12/31)
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- BENZIMIDAZOLE DERIVATES USEFUL AS INHIBITORS OF MAMMALIAN HISTONE DEACETYLASE ACTIVITY
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A compound of formula (I) or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising the compound. The compound is useful in therapy, for the treatment of disorders mediated by HDAC6, such as autoimmune disorders, neurodege
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Page/Page column 66-67
(2016/11/28)
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- Mesomorphism dependence on heterocyclic end group
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An ester homologous series containing a heterocyclic end group was synthesized and studied with a view to understanding and establishing the effect of molecular structure on liquid crystal behavior. The novel series consists of 13 homologues. All members of the series are enantiotropically smectogenic without exhibition of nematogenic character. The textures of smectogenic homologues are of the type smectic A or C. The transition temperatures were determined by an optical polarizing microscope equipped with a heating stage. The Sm-I transition curve in a phase diagram behaves partly in an abnormal manner with the exhibition of an odd-even effect. The average thermal stability for smectic is 141.45°C and the mesomorphic phase length ranges from 8.1°C to 30.3°C. Analytical and spectral data confirm the molecular structures. The liquid crystal properties of present series are compared with the structurally similar known homologous series.
- Bhola,Bhoya
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- Dependence of mesomorphism on molecular rigidity of nonlinear and linear isomeric and nonisomeric chalconyl esters
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The novel thermotropic liquid crystalline (LC) materials have been synthesized and studied through chalconyl ester nonlinear (meta substituted) homologous series RO-C6H4?CH?CH?COO?C6H4-CO?CH?CH?C6H4-OC14H29(n) with a view to understand the effect of molecular structure on LC behavior with reference to determine the difference between linear and nonlinear shaped molecules. Novel series consisted of thirteen members, whose nematogenic enantiotropic mesomorphism commences from C6 homologue and continued up to C18 homologue with the absence of smectogenic character. C1 to C5 homologues are nonliquid crystals as determined through an optical polarising microscope (POM) equipped with a heating stage. Transition temperatures of LC homologues alternate and are lower than the corresponding n-alkoxy cinnamic acids. Cr-N/I and N-I transition curve behaved in normal manner. N-I transition curve exhibited odd-even effect in a phase diagram. Textures of nematic phase are threaded or Schlieren or determined by miscibility method and from observing mesophase on the top of the POM. Thermal stability for nematic is 92.5 and mesophase length minimum to maximum is 19.0 to 32.0°C at the C10/18and C6 homologue. Group efficiency order on the basis of thermal stability is (Formula presented.) Thus, novel series is nematogenic and low melting type. Analytical and spectral data confirmed the molecular structures of homologues.
- Jain,Patel
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- Mesomorphism dependence on halogenated chalconyl esters in terms of molecular flexibility/rigidity
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Vinyl carboxy central group containing a novel chalconyl ester homologous series: RO.C6H4.CH ? CH.COO.C6H4.CH ? CH.CO.C6H4.I (para) have been synthesized and studied with a view to understand and establish the relation between thermotropic liquid crystalline (LC) behaviors and the molecular structure. Novel chalconyl ester homologous series consists of thirteen homologs (C1–C18). C1–C3 homologs are nonmesogenic, C4 homolog is enantiotropic nematogenic and the rest of the homologs (C5–C18) are enantiotropically smectogenic plus nematogenic. Phase transition temperatures and textures of LC phase were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Cr-M/I, Sm-N, N-I transition curves in a phase diagram behaved in normal manner. Sm-N and N-I transition curves exhibited odd-even effect from C4–C10 or nearby C10 homolog. Textures of nematic phase are threaded or Schlieren and that of the smectic phase are of the type smectic A or C. Analytical and spectral data confirms the molecular structure of homologs. Thermal stabilities for smectic and nematic mesophases are 155.0 and 180.7, respectively, and their corresponding mesophaselengths are varied from minimum to maximum at 17.0°C–39.0°C as well as 15.0°C–30.0°C. Thus, it is middle ordered melting type series. The group efficiency orders derived on the basis of smectic and nematic thermal stabilities are as under: Sm: -C6H4.I > -C6H4.Cl > -C4H3S and N:- C6H4.I > -C6H4.Cl > -C4H3S from comparative study of structurally similar analogous series
- Sharma, Vinay S.,Patel
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- Mesomorphism dependence of a terminal or lateral alkoxy group
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A novel homologous series of thermotropic mesomorphs has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on mesomorphic properties with reference to rigidity and flexibility of the homologues series: RO-C6H4-CH?CH-CO-C6H4-OC18H37(n). The novel homologous series comprises 13 novel homologues (C1 to C18), from which 11 homologues are enantiotropically mesogenic (C3 to C18). Smectogenic mesophase commences from C7 homologue, and nematogenic mesophase is exhibited by C3 to C18 homologues in enantiotropic manner. Thus, C7 to C18 homologues are enantiotropically smectogenic plus nematogenic. Textures of smectic phase are of the type A or C, and that of nematic phase are threaded or Schlieren as confirmed through an optical polarizing microscope equipped with a heating stage. Transition curve of a phase diagram behaved in a normal manner except N-I transition curve, which shows minor deviating trend (C12 to C18) from expected normal behavior. An odd-even effect is exhibited by N-I and Sm-N transition curves. Analytical, spectral, and thermal data confirm the molecular structures of novel homologues. Thermal stabilities for smectic and nematic are 52.7°C and 66.6°C, respectively, whose total mesophase lengths range from 12.0°C to 28.0°C. Thus, novel series of chalcones is a low melting series whose mesogenic transition temperatures vary between 38.0 and 86.0°C.
- Solanki, Ravindra,Patel
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- Dependence of mesomorphism on molecular rigidity of chalconyl liquid crystals with two phenyl rings
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A novel homologues series: RO-C6H4?CH=CH?CO?C6H4?OC16H33(n) (meta) of chalcones with two phenyl rings is synthesized and studied with a view to understanding and establishing the relationship between molecular structure and mesogenic behavior. The series consists of 13 homologues (C1 to C18). Mesomorphism commences from the second member of the series. C2 to C6 homologues are enantiotropicnematic and the rest of the homologues (C7 to C8) are monotropicnematic plus monotropicsmectic. C1 homologue is nonmesogenic. Transition temperatures were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of nematic and smectic phases are threaded, Schlieren or smectic-A, respectively, as judged directly from the heating top of microscopic observations. Thermal, analytical and spectral data confirms the molecular structures. Thermal stabilities for smectic and nematic are few (1 or 2°C) degrees and 72.6°C, respectively. The mesophase lengths are relatively shorter with low mesomorphic transition temperatures (44.0°C to 85.0°C).
- Sharma, Vinay S.,Patel
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- Synthesis, characterization and study of liquid crystal properties of new homologous chalcone series
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Onenewmesogenic homologous series of chalconyl derivativewith two ring (3/-(4/- (decyloxy) phenyl-1-(4-(alkoxy) phenyl) prop-2-en-1-one) has been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In the series, the lower members (C4 and C5) exhibit only enantiotropic nematic mesophase but middle and higher members exhibit enantiotropic nematic as well as smecticmesophase. The nematicmesophase commence from C4 homologue and smectic mesophase (smectic-A type texture) commence from C6 homologue as enantiotropic and persists up to the lastmember synthesized. The mesomorphic properties of present serieswere compared with other two structurally similar series to study the effects of change of meta and para position on the mesomorphism.
- Jain,Patel
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- Synthesis and study of new homologous series of ester-chalcone exhibiting nematic phases
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A novel homologous series of ester-chalcone have been synthesized and their liquid crystals (LCs) properties are studied. All the homologue shows nematic phase except C1-C4 homologue. Classical nematic textures are observed in this homologous series with the help of polarizing optical microscope (POM) equipped with hot stage. The role of flexible methylene group spaces, degree of polymerization and central linkage on the exhibition of all the homologue is discussed. The novel homologous series has been characterized by the standard methods (1HNMR, IR, and elemental analysis).
- Jain,Patel
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- Mesomorphism and molecular flexibility in novel chalconyl derivatives with two phenyl rings
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A novel chalconyl liquid crystalline (LC) homologous series with two phenyl rings and one central bridge RO?C6H4?CH=CH–CO?C6H4(O?C18H37) (meta) has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC behaviors or properties. Homologous series of present investigation (C1–C18) consists of thirteen homologues, and thermotropic mesomorphism for nematic and smectic commences from C3 and C6 homologues respectively. The C3, C4, and C5 homologues are enantiotropically nematic, whereas, the homologues from C6 to C18 are monotropically smectic plus nematic. Melting points and transition temperatures were determined using a polarizing optical microscope (POM) equipped with a heating stage. The textures of the nematic phase are threaded or Schlieren and that of a smectic phase are fan shaped of smectic-A or smectic-C type. The Cr?I/M, N?I/I?N, and N-Sm transition curves behave in the normal manner, and the Cr-I/M exhibits an odd-even effect. Analytical, thermal, and spectral data confirm the molecular structures. Thermal stabilities of smectic and nematic are low. Mesophase lengths are very short, ranging between 1–8°C and 14°C. The novel compounds are compared with a known series.
- Sharma, Vinay S.,Jain,Patel
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- Mesomorphism dependence on heterocyclic tail
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A novel homologous series of liquid crystal materials containing a heterocyclic ring was synthesized with a view to understanding and establishing the relation between liquid crystal (LC) properties and a molecular structure; and with a view to curing skin-related diseases following biological activity studies. The series consist of 13 (C1 to C18) members. All the members are liquid crystals. The C4 to C18 members are smectogenic of which C4 and C5 are monotropic and remaining members (C6 to C18) are enantiotropic in nature; whereas all C1 to C18 members are enantiotropically nematogenic. Hence the C1, C2, C3 members are only nematogenic and the rest of the homologues are smectogenic in addition to nematogenic. Transition temperatures were determined by an polarizing optical microscope equipped with heating stage. Analytical and spectral data confirmed the molecular structures of homologues. It is a middle ordered melting type series. LC properties of a series are compared with the structurally known series.
- Bhola,Bhoya
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- Mesomorphism dependence on central bridges and the efficiency order of the tail group
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A novel homologous series: RO-C6H4?CH?CH?COO?C6H4?CH?N-C6H3 (CH3)2 of ortho-meta Schiff's bases has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on mesomorphic properties and to provide a source of novel liquid crystalline (LC) materials. The series consists of 13 homologues (C1 to C8, C10, C12, C14, C16 & C18). C1 and C3 homologues are nonmesomorphic, C2 and C4monotropicnematic, C6 and C7monotropicsmectic in addition to enantiotropicnematic, C5 is only enantiotropicnematic, C8, C10, C12 are enantiotropically smectogenic plus nematogenic and C14, C16, C18 homologues are enantiotropically smectic only. Textures and transition temperatures were determined using an optical polarizing microscope equipped with a heating stage. Analytical and spectral data confirm the molecular structures. Average smectic and nematic thermal stabilities are 100.16°C and 110.83°C, respectively. Mesomorphic properties of present novel series are compared with structurally similar homologous series.
- Bhola,Bhoya
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p. 154 - 161
(2016/07/14)
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- DIAMINOGUANIDINE DERIVATIVES AND APPLICATION THEREOF IN PREPARATION OF ANIMAL GROWTH PROMOTERS USED IN FEED
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Diaminoguanidine derivatives in preparation of animal growth promoters used in feed. The diaminoguanidine derivatives have a structural formula as shown in formula (I), wherein R1 is methyl, ethyl, isopropyl, n-butyl, n-propyl, n-pentyl, n-octyl, n-tetradecyl, sec-butyl, 3-pentyl, cyclopentyl or benzyl. The diaminoguanidine compounds significantly improve the productivity of ducks if they are fed with the diaminoguanidine compounds. Productivity of pigs or chickens is also improved with such diaminoguanidine compounds.
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Paragraph 0074; 0075
(2016/12/12)
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- Mesomorphism and flexibility of alkyl chains in chalcone esters
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A novel homologous series of chalconyl ester liquid crystals (LCs): RO?C6H4–CH:CH–COO?C6H4–CO?CH:CH?C6H4–OC10H21 (n) (para) has been synthesized and studied with a view to understanding and establishing the relationship between molecular structure and LC properties with reference to flexibility of the terminal chain. The novel series consists of eleven homologs (C1–C16). The C1 and C2 homologs are nonliquid crystals and the rest of the homologs (C3–C16) are enantiotropic nematic without exhibition of smectic mesophase. Transition and melting temperatures were determined by an optical polarizing microscope equipped with a heating stage. Textures of nematic phases are threaded or Schlieren. Cr-N/I transition curve adopts a zigzag path in a normal manner with overall descending behaviors. The N-I transition curve exhibits a sharp and shorter odd-even effect from C3 to C6 and it diminishes from and beyond C6 for higher homologs of longer n-alkyl chain (R) in more or less or negligible deviating manner from normal descending tendency. Thermal stability for the nematic is 116.4°C and mesophase length ranges from 19°C to 67°C at the C3 and C12 homolog respectively. The LC properties of present novel series are compared with structurally similar analogous series to derive group efficiency order.
- Muniya,Patel
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- The effect of geometrical shape and molecular rigidity on mesomorphism
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A novel nonlinear homologous series RO?C6H4?CH?CH?COO?C6H4 (meta) ?CO?CH?CH?C6H4?OC12H25(n) (para) consisting of three phenyl rings, two central bridges ?CH?CH?COO? and ?CO?CH?CH? as well as ?OR and ?OC12H25(n) as flexible and constant terminal end groups respectively. The object in view is aimed to understand and establish the effect of molecular structure on LC properties of nonlinear inverted “V” shaped molecules. Novel homologous series consists of thirteen homologues. Transition temperatures and textures were determined by polarizing optical microscopy (POM) equipped with a heating stage. Textures of nematic phases are threaded or schlieren and that of a smectic phases are of the type-A or C. Transition curves of a phase diagram behaved in a normal manner. Sm-N and N-I transition curves exhibited odd-even effect. Analytical, Thermal and Spectral data confirms the molecular structure of homologues.
- Patel, Priya K.,Shah
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- Indium(III) Isopropoxide as a Hydrogen Transfer Catalyst for Conversion of Benzylic Alcohols into Aldehydes or Ketones via Oppenauer Oxidation
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Indium(III) isopropoxide [In(Oi-Pr)3] was applicable as an Oppenauer oxidation catalyst, and the conversion of primary or secondary alcohols into the corresponding aldehydes or ketones was promoted at room temperature using pivalaldehyde as an oxidant.
- Ogiwara, Yohei,Ono, Yuji,Sakai, Norio
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p. 4143 - 4148
(2016/11/26)
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- Mesomorphism dependence on geometric shapes in isomeric molecules
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A novel homologous series of symmetrical dimers RO-C6H4-CH?CH-COO-C6H4-OOC-CH?CH-C6H4-OR of liquid crystalline (LC) characteristics have been synthesized and studied with a view to understand and establish the effects of the molecular structure on the LC property or properties with special reference to geometrical shape in case of isomeric series. Homologous series consisted of 13 dimers (C1 to C18). C1 to C8 are only enantiotropic nematic and the rest of the dimer homologues from C10 to C18 are enantiotropically smectogenic in addition to nematogenic. Textures of the nematic phase are threaded or Schlieren and that of the smectic phase are of the type smectic A or C. Transition temperatures and the textures were determined by an optical polarizing microscopy equipped with a heating stage. Thermal stability for smectic and nematic are 161.0 °C and 237.6 °C, respectively, whose total mesophase (Sm+N) length ranges from 71.0 °C to 126.0 °C. Cr–M, Sm–N, and N–I transition curves of a phase diagram behaved in normal manner except negligible abnormality at C14 dimer of N–I transition curve. N–I transition curve exhibited odd– even effect nearby up to C7 dimer. Analytical and spectral data supported molecular structures of homologue dimers. Thus, present homologue dimer series is predominantly nematogenic and partly smectogenic and high-ordered melting type. LC properties of present novel series are compared with structurally similar series.
- Bhola,Bhoya
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p. 112 - 120
(2016/07/14)
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