- Light-Promoted Nickel Catalysis: Etherification of Aryl Electrophiles with Alcohols Catalyzed by a NiII-Aryl Complex
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A highly effective C?O coupling reaction of (hetero)aryl electrophiles with primary and secondary alcohols is reported. Catalyzed by a NiII-aryl complex under long-wave UV (390–395 nm) irradiation in the presence of a soluble amine base without any additional photosensitizer, the reaction enables the etherification of aryl bromides and aryl chlorides as well as sulfonates with a wide range of primary and secondary aliphatic alcohols, affording synthetically important ethers. Intramolecular C?O coupling is also possible. The reaction appears to proceed via a NiI–NiIII catalytic cycle.
- Cao, Rui,Lai, Chu-Hui,Li, Gang,Liu, Fengyi,Lu, Huan-Huan,Wang, Chao,Xiao, Jianliang,Xue, Dong,Yang, Liu,Zhang, Wei
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supporting information
p. 12714 - 12719
(2020/06/02)
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- Oxalic Diamides and tert-Butoxide: Two Types of Ligands Enabling Practical Access to Alkyl Aryl Ethers via Cu-Catalyzed Coupling Reaction
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A robust and practical protocol for preparing alkyl aryl ethers has been developed, which relies on using two types of ligands to promote Cu-catalyzed alkoxylation of (hetero)aryl halides. The reaction scope is very general for a variety of coupling partners, particularly for challenging secondary alcohols and (hetero)aryl chlorides. In case of coupling with aryl chlorides and bromides, two oxalic diamides serve as the powerful ligands. The tert-butoxide is first demonstrated as a ligand for Cu-catalyzed coupling reaction, leading to alkoxylation of aryl iodides complete at room temperature. Additionally, a number of carbohydrate derivatives are applicable for this coupling reaction, affording the corresponding carbohydrate-aryl ethers in 29-98% yields.
- Chen, Zhixiang,Jiang, Yongwen,Zhang, Li,Guo, Yinlong,Ma, Dawei
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supporting information
p. 3541 - 3549
(2019/02/26)
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- Columnar self-assembly of bowl shaped fluorescent liquid crystals based on calix[4]arene with Schiff base units
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A new family of bowl-shaped molecules with a calix[4]arene rigid core and appended on four-sides, that display a wide range of hexagonal columnar phases, has been synthesised and well characterized. The thermal behaviours of the present compounds were established using a combination of polarising optical microscopy (POM), differential scanning calorimetry (DSC) and a high-temperature powder X-ray diffraction method (XRD). It is found that all of the synthesised materials show an enantiotropic hexagonal columnar liquid crystal phase. The structural and conformation characterization of these newly synthesised compounds was achieved by FT-IR, 1H NMR, and 13C NMR spectroscopy. All of the synthesised compounds exhibited good blue luminescence in solution under long wavelength UV light. To explore the structure property correlations, the alkoxy side chain group was varied from a lower alkyl spacer to a higher alkyl spacer on the lower rim of the calix[4]arene. The present research specified that the introduction of linking groups on the lower rim with an n-alkoxy side group is an influential approach to obtaining a supramolecular bowl shape liquid crystal which has good thermal and photophysical behaviour.
- Sharma, Anuj S.,Sharma, Vinay S.,Vekariya, Rajesh H.
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supporting information
p. 15044 - 15051
(2018/09/29)
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- Synthesis and mesomorphic properties of 2,4-bis(4′-n-pentyloxybenzoyloxy)- benzylidine-4″- n-alkoxyaniline
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The synthesis and mesomorphic properties of a new series of 2,4-bis(4′-npentyloxybenzoyloxy)- benzylidine-4″ -n-alkoxyaniline (DC5An) are reported. The molecular structure of compounds was confirmed by FTIR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibit nematic (N) and smectic C (SmC) phases. The first four homologues (DC5A1-DC5A4) display a N mesophase, whereas the highest homologues (DC5A5-DC5A10) exhibit an enantiotropic dimorphism N and SmC phases. The mesomorphic properties of the present series are compared and discussed with other structurally related series.
- Hamad, Wali M.,Azeez, Hashim J.,Al-Dujaili, Ammar H.
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- Dependence of LC state on molecular flexibility
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A novel azoester homologous series of liquid crystals (LCs) viz. RO?C6H4COOC10H6-N?N(ortho)-C6H4?OC4H9(para) has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on LC properties. Homologous Series consists of thirteen members (C1 to C18). C1 to C3 members are nonliquid Crystals and the rest of the homologues are LC in an enantiotropic manner. C7 to C18 are smectogenic in addition to nematogenic whereas C4, C5, and C6 are only nematogenic. The Sm-N and N?I transition curves behave in a normal manner with the usual exhibition of an odd–even effect. The Cr-M/I curve also behaves in a normal manner. Analytical and spectral data confirm the molecular structures of homologues. The average smectic and nematic thermal stabilities are 60.31°C and 79.6°C, respectively, with total mesophase length varying minimum to maximum is 21°C to 57°C at the C6 and C14 homologue, respectively. Thus, present novel azoester homologous series is partly smectogenic and predominantly nematogenic with low ordered melting type and useful to construct LC devices workable at low temperatures or room temperature.
- Jadeja,Sharma, Vinay S.,Jain,Patel
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p. 144 - 153
(2016/07/14)
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- Study of mesomorphism dependence on molecular flexibility of an azoester series containing a napthyl unit
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A novel azoester homologous series of liquid crystalline (LC) compounds: RO?C6H4-COO?C10H6-N:N-C6H4?OC4H9(n) without lateral substitution has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC substances with reference to tailed-end group. The novel homologous series consists of 13 homologs (C1 to C18) whose nematogenic and smectogenic mesomorphism commences enantiotropically from C6 and C12 members of the series, respectively. The C12–C18 homologs are smectogenic and C6–C18 are nematogenic, of which C12–C18 homologs are smectogenic plus nematogenic. The C1–C5 homologs are nonmesogenic. Transition temperatures and the textures of the homologs were determined and identified by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren and that of the smectic phase are of the type A or C. Transition curves Cr-M/I, Sm-N and N-I of a phase diagram behaved in normal manner except N-I transition temperature of C10 homolog which deviated by 9°C–10°C from normal behavior. N-I transition curve exhibited odd-even effect. Analytical, spectral, and thermal data confirms the molecular structures of homologs. Thermal stability for smectic and nematic are 115.5°C and 138.5°C, respectively whose corresponding mesophaselengths are varied from 10.0°C to 16.0°C and 13.0°C to 24.0°C, respectively. Group efficiency order for smectic and nematic are derived from comparative study of structurally similar analogous series; as smectic: ?OC4H9 (n) > ?CH3 > ?H; Nematic: ?H > ?OC4H9 (n) > ?CH3
- Jadeja,Patel
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- The effect of molecular rigidity and flexibility on the mesomorphism of azoesters
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ASBTRACT: An Azoester novel homologous series RO-C6H4-COO-C6H4-N?N-C6H4-OC4H9(n) (para) of liquid crystalline (LC) materials are synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal behavior with reference to lateral, terminal, or central group or groups on the basis of molecular rigidity and/or flexibility. The novel homologous series consists of thirteen (C1 to C18) homologues. C1 to C5 homologues are nonmesogenic and the rest of the homologues are enantiotropically mesogenic. C8 to C18 homologues are smectogenic plus nematogenic and the remaining two C6 and C7 homologues are only nematogenic without exhibition of smectic property. Analytical, thermal and spectral data confirms the molecular structures. Textures and transition temperatures of homologues were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phases are threaded or Schlieren and that of a smectic phase are of the type of A or C. The average thermal stabilities for smectic and nematic are 111.3°C and 124.7°C, respectively. The smectic and nematicmesophase lengths from 10.0°C to 28.0°C and 7.0°C to 16.0°C, respectively. The transition temperatures are compared with known series.
- Jadeja,Patel
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- AZOBENZENE COMPOUND AND HEAT PUMP SYSTEM USING THE SAME
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PROBLEM TO BE SOLVED: To provide an azobenzene compound capable of repeated structural changes without heating, and a heat pump system using the same. SOLUTION: An azobenzene compound represented by the general formula (1) and undergoing cis-trans isomerization reaction upon light irradiation is used as a heat medium of a heat pump system. In the formula, at least one of R1 to R3 is (CH2CH2O)n-R10; R4 is R11, O-R11, NH-R11, or COO-R11; X- is Cl-, Br-, I-, BF4-, PF6-, CH3(CH2)nSO3-, TsO-, (YSO2)2 N-, or (NC)2 N-; n is an integer between 0 and 2; and Y is F, CF3, or C2F5. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0074; 0076
(2016/10/10)
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- Photoliquefiable ionic crystals: A phase crossover approach for photon energy storage materials with functional multiplicity
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Ionic crystals (ICs) of the azobenzene derivatives show photoinduced IC-ionic liquid (IL) phase transition (photoliquefaction) upon UV-irradiation, and the resulting cis-azobenzene ILs are reversibly photocrystallized by illumination with visible light. The photoliquefaction of ICs is accompanied by a significant increase in ionic conductivity at ambient temperature. The photoliquefaction also brings the azobenzene ICs further significance as photon energy storage materials. The cis-IL shows thermally induced crystallization to the trans-IC phase. This transition is accompanied by exothermic peaks with a total ΔH of 97.1 kJmol-1, which is almost double the conformational energy stored in cisazobenzene chromophores. Thus, the integration of photoresponsive ILs and self-assembly pushes the limit of solar thermal batteries.
- Ishiba, Keita,Morikawa, Masa-Aki,Chikara, Chie,Yamada, Teppei,Iwase, Katsunori,Kawakita, Mika,Kimizuka, Nobuo
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supporting information
p. 1532 - 1536
(2015/02/05)
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- Exploitation of a Candida antarctica lipase B-catalysed in situ carboxylic acid activation method for the synthesis of acetanilides
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An efficient biocatalytic method has been developed which provides acetanilides in good yields which are otherwise inaccessible using Candida antarctica lipase B. The process exploits the enzyme-catalysed synthesis of an acyl donor and its in situ reaction with anilines. The method is potentially useful for the synthesis of bulky acetanilides since amide formation occurs through an active site-independent step.
- Lal, Samridhi,Snape, Timothy J.
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- A molecular insight on the supramolecular assembly of thiophene polymers
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Herein, the relationship between supramolecularly self-assembled microstructures and the chemical structures of photoluminescent molecules is discussed. A series of non-amphiphilic molecules with different length alkyl chains (4-14), central mesogenic groups, and chemical linkers were designed and synthesized. Intricate analysis shows that the supramolecular assembly varies with change in torsion angle of the thiophene linking group on elongation of the alkyl chain. Small angle X-ray scattering measurement shows long range molecular interaction for lower alkyl chain length, AFM reveals circular domains for octyl and decyl alkyl group polymers. UV-Visible and photoluminescence studies in solution and thin-film show that the J-aggregate patterns for the circular domain of the polymer backbone has a major effect on the polymer absorbance, and produces a larger shift for the photoluminescence signals at higher wavelengths. Excitation polarisation studies show a change in molecular ordering in various colour regions with change in aggregation by means of maximum dichroic ratio for the circular domain assembly. Charge carrier mobility and cyclic voltammetry studies show higher mobility and reduced band gap for these circular domain polymers. Dynamic light scattering studies of octyl alkyl chain polymers show a bimodal distribution, which shows the apparent nature of anisotropy in solution. The Royal Society of Chemistry.
- Suryanarayanan, Chandrasekaran,Ravindran, Ezhakudiyan,Ananthakrishnan, Soundaram Jeevarathinam,Somanathan, Narayanasastri,Mandal, Asit Baran
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p. 18975 - 18982
(2012/10/29)
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- Influences of hydrogen bonding and peripheral chain length on mesophase structures of mesogen-jacketed liquid crystalline polymers with amide side-chain linkages
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A series of mesogen-jacketed liquid crystalline polymers, poly{2,5-bis[(4-alkoxyphenyl)aminocarbonyl]styrene} (P-Cm, where m is the number of carbon atoms in the alkoxy groups, and m = 1, 4, 8, 12), with an amide core and flexible tails of varying lengths on the two ends in the side chain were designed and successfully synthesized via conventional radical polymerization. The mesophase structures of these polymers were dependent on the number of carbon atoms in the peripheral chains. Wide-angle X-ray diffraction and polarized light microscopy results revealed that the polymers with m ≥ 4 could form smectic A phases, while a columnar nematic phase could be formed for the polymer with methoxy end groups (P-C1). The hydrogen bonding among the side-chain amide groups might play an important role in forming and stabilizing these liquid crystalline phases, which was suggested by the results from variable-temperature FTIR and 2D IR analyses.
- Cheng, Yan-Hua,Chen, Wen-Ping,Shen, Zhihao,Fan, Xing-He,Zhu, Mei-Fang,Zhou, Qi-Feng
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experimental part
p. 1429 - 1437
(2011/10/07)
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- Studies of calamitic liquid crystalline compounds involving ester-azo central linkages with a biphenyl moiety
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Two mesogenic homologous series involving ester-azo central linkages with a biphenyl moiety have been synthesized, such as 4'-[(4-n-alkoxyphenyl)diazenyl] biphenyl-4-ol (series I) and 4'-[(4-n-alkoxyphenyl) diazenyl]-4-butoxy phenyl biphenyl-4-carboxylate (series II). Azobiphenyl of series I having a free hydroxyl group with strong hydrogen bonding exhibits a high-temperature enantiotropic smectic phase. Whereas in series II, compounds containing C 1-C8 carbon atoms exhibit only a monotropic smectic phase and compounds with C10, C12, C14, and C 16 atoms show an enantiotropic smectic phase. These compounds were characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectral studies. The phase transition and mesogenicity of these substances were studied by polarizing optical microscopic and differential scanning calorimetric techniques. Their thermal stabilities and other characteristics are discussed. Copyright Taylor &Francis Group, LLC.
- Thaker,Dhimmar,Patel,Solanki,Patel,Chothani,Kanojiya
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experimental part
p. 172 - 191
(2012/07/27)
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- Role of terminal heterocyclic ring on mesomorphic properties of homologous series
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Two new homologous series of compounds with a heterocyclic ring having sulfur and oxygen as a hetero atom derived from p-hydroxy acetophenone and alkoxy aniline containing cinnamate-azomethine as central linkages have been synthesized. viz. 4(furalacryloxy) α-methyl benzylidine-4′-alkoxy aniline and 4(thianylacryloxy) α-methyl benzylidine-4′-alkoxy aniline. The compound of both the series have been characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectrometry method. Their liquid crystalline properties have been investigated by optical polarizing microscopy and differential scanning calorimetry (DSC) studies. All the derivatives are mesomorphic in nature showing the nemetic phase. The mesomorphic properties of the present two series are compared with other structurally related series to evaluate the effect of thiophene and furan on mesomorphism. Copyright Taylor & Francis Group, LLC.
- Thaker,Patel,Solanki,Dhimmer,Dave
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experimental part
p. 63 - 80
(2010/09/05)
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- Symmetrical and unsymmetrical analogues of isoxyl; active agents against Mycobacterium tuberculosis
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Symmetrical and unsymmetrical analogues of the antimycobacterial agent isoxyl-have been synthesized and tested against Mycobacterium tuberculosis H37Rv and Mycobacterium bovis BCG, some showing an increased bactericidal effect. In particular, compounds 1-(p-n-butylphenyl)-3-(4-propoxy-phenyl) thiourea (10) and 1-(p-n-butylphenyl)-3-(4-n-butoxy-phenyl) thiourea (11) showed an approximate 10-fold increase in in vitro potency compared to isoxyl, paralleled by increased inhibition of mycolic acid biosynthesis in M. bovis BCG. Interestingly, these isoxyl analogues showed relatively poor inhibition of oleate production, suggesting that the modifications have changed the spectrum of biological activity.
- Bhowruth, Veemal,Brown, Alistair K.,Reynolds, Robert C.,Coxon, Geoffrey D.,Mackay, Simon P.,Minnikin, David E.,Besra, Gurdyal S.
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p. 4743 - 4747
(2008/12/23)
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- An efficient lutidine-assisted etherification of phenols with alkyl chloride in water
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An efficient etherification of phenol derivatives with alkyl chloride in water was achieved. The reactivity of the ether bond forming reaction was activated by addition of 2,6-lutidine.
- Aki, Shinji,Nishi, Takao,Minamikawa, Jun-Ichi
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p. 940 - 941
(2007/10/03)
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- Mesogenicity of organophosphazenes: The effect of phosphazene rings and side groups on the phase transition
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Cyclotriphosphazene and cyclotetraphosphazene derivatives with mesogenic 4-N-(4-alkoxyphenyl)iminomethyl)phenoxy and 4-(4′-alkoxy) biphenoxy moieties were synthesized. Schiff base moiety has higher mesomorphic stability than that in biphenyl moiety both in cyclotriphosphazene and cyclotetraphosphazene. Cyclotriphosphazenes possess higher thermal stability in the mesomorphic phase than the cyclotetraphosphazenes, suggesting the difference in the molecular structure.
- Moriya, Keiichi,Yamane, Toshihiro,Suzuki, Toshiya,Masuda, Tsuyoshi,Mizusaki, Hiroshi,Yano, Shinichi,Kajiwara, Meisetsu
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p. 1427 - 1432
(2007/10/03)
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- Design, synthesis and biological testing of a novel series of anti-inflammatory drugs
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Many of the non-steroidal anti-inflammatory drugs (NSAIDs) currently marketed produce severe gastro-toxic side effects. The benefits of producing NSAIDs without these side effects are obvious, particularly for patients requiring long-term therapy. The aim of this investigation was to produce novel NSAIDs, based on paracetamol, that exhibit little or no gastro-toxicity. The work covers design, synthesis and testing of 13 drug candidates. The analgesic and anti-inflammatory potencies of the drug candidates were measured using the mouse abdominal constriction assay and the carrageenan-induced rat paw oedema assay, respectively. The stomachs of the rats were examined post-mortem, to assess the gastro-toxicity of the drugs. Of the 13 compounds described herein, 11 were shown to possess analgesic activity at 2-10 times the potency of aspirin, while 8 demonstrated anti-inflammatory activity at 3-10 times the potency of aspirin. Significantly, all of the compounds showed very low gastro-toxicity when compared with aspirin. The results of this study indicate that it is possible to develop novel, potent NSAIDs based on the structure of paracetamol. These compounds have the advantage of demonstrating much lower gastro-toxicity than NSAIDs currently available. Drugs of this type may, in future, provide effective treatments for inflammatory disorders.
- Duffy,Dearden,Rostron
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p. 1505 - 1514
(2007/10/03)
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- Mesogenic biphenyl derivatives with azo and ester central linkage
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Biphenyl nucleus comprises one of the most interesting research areas in the study of relations between chemical constitution and mesomorphic properties. Few biphenyl derivatives with azo and ester central linkage having following general formula have been synthesized and their mesomorphic properties were evaluated. Where R=-H, -OCH3, R'=-CH3, -OCH3, -OC2H5, -OC4H9; X=-H, -Br. All the synthesized compounds were characterized by elemental analysis and spectroscopic methods.
- Prajapati
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p. 769 - 777
(2007/10/03)
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- Synthesis and structure of 1,4-diazabutadiene liquid crystals
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Nine 1,4-diazabutadiene compounds, Ar-N=C(R)-C(R)=N-Ar, R=H, Me; Ar= H2n+1CnO-C6H4, 2,4-(H9C4O)(Me)-C6H3 were synthesized and their liquid crystal properties were studied through thermal polarizing microscopy. The X-ray single crystal structure of compound 9 (Ar-N=C(H)-C(H)=N-Ar, Ar=2,4-(Me)(H9C4O)C6H3) was tested. It is a monoclinic crystal system, space group P21/C with the unit cell parameters: a=7.0703(3)A, b=8.674(4)A, c=18.3115(8)A, β =95.392(1)°. V=1114.57(9)A3, z=2, Dc=1.134 Mg/m3, R=0.0490,Rw=0.1237.
- Zhao, Ke-Qing,Hu, Pin,Xu, Hong-Bo
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p. 801 - 808
(2007/10/03)
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- Synthesis of new metallomesogens containing Ni(II) and Cu(II) atoms
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A few new metallomesogens containing Ni(II) and Cu(II) atoms of the ligands 4-substituted 2′-hydroxy 4′(4″-n-hexadecyloxybenzoloxy)azobenzenes have been synthesized. The complexes have been characterized by C, H, N, microanalysis, IR, NMR and UV-Visible spectroscopies. Meso-morphic properties of all the ligands and complexes were investigated on a Leitz Laborlux 12 POL microscope provided with a heating stage.
- Prajapati,Shah
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- Smectic mesophase properties of dimeric compounds. 2. Distinct formation of smectic structures with antiferroelectric ordering and frustration
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We have prepared two series of dimeric compounds, which comprise the schiff's base mesogen, alkyl spacer with the carbon number of 5 and alkyl or alkoxy tail with the carbon number of m = 4 approx. 16. In these compounds, we observed three types of smectic liquid crystals, the single layer phase with the tail group randomly mixing with the spacer, the bilayer phase in which the segregation of the spacer and tail groups takes place and so two mesogenic layers are included within a repeat unit, the frustrated smectic phase in which the density modulation appears along the layer as well as the layer normal. The bilayer phase was found to be antiferroelectric and the frustrated smectic phase was considered to result from the two dimensional escape from the dipolar interaction. The phase behaviour with m and the structure and properties of each phase will be described in detail.
- Watanabe, Junji,Izumi, Tatuya,Niori, Teruki,Zennyoji, Masahito,Takanishi, Yoichi,Takezoe, Hideo
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- Polymer Supported Acetylaminophenoxide Anion: Convenient Method for O-Alkylation
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Alkylation of acetylaminophenoxide supported on Amberlyst A-26 gives O-alkylated products in high yields and purity.In addition to ease and simplicity of the method and regeneration of polymeric by-product, the polymeric reagent seems to increase the nucleophilicity of the anions.
- Salunkhe, D. G.,Jagdale, M. H.,Shinde, S. S.,Salunkhe, M. M.
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- Comparative Structure-Activity Relationships of Antifolate Triazines Inhibiting Murine Tumor Cells Sensitive and Resistant to Methotrexate
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The inhibitory effect of 108 4,6-diamino-1,2-dihydro-2,2-dimethyl-1-(substituted-phenyl)-s-triazines on murine L5178Y tumor cells, resistant and sensitive to methotrexate (MTX), has been studied.From the pI50 values, quantitative structure-activity relationships have been formulated which show that the lipophilic triazines are much more inhibitory against resistant cells than methotrexate or hydrophilic triazines.The results are compared with the behavior of other antifolate drugs that have been used in chemotherapy, as well as with eight antitumor drugs that are notantifolates.The acquired resistance of these cells toward hydrophilic antifolates may be attributed to the combined effect of an impaired active-transport system, a change in the conformation of dihydrofolate reductase in the resistant cells, and an amplified production of dihydrofolate reductase in the resistant cells.
- Selassie, Cynthia Dias,Hansch, Corwin,Khwaja, Tasneem A.,Dias, Cecilia B.,Pentecost, Stephanie
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p. 347 - 357
(2007/10/02)
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