- Effect of the thermal history on the thermal and rheological behavior of a thermotropig polyester
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The biphasic behavior and phase transitions of a thermotropic mainchain liquid crystalline polyester, the poly(oxytrimetilen-etilen glycol p,p'bibenzoate), was studied by X-ray diffractometry, differential scanning calorimetry (DSC), and rotational rheometry. The liquid crystalline mesophase structure of the polymer evolves from Smectic C to Smectic A at around 100°C and changes to the isotropic state at about 200°C. The annealing of polymer samples at different temperatures within the smectic-isotropic transition gives rise to double endotherm and exotherm peaks on the heating and cooling DSC traces. These peaks are attributed to the preferential segregation of the lower molecular weight molecules from the liquid crystalline to the isotropic phase in the biphasic zone. The Theological studies are consistent with this result. The dynamic moduli measured at constant frequency in temperature ramps using polymer samples with, different thermal histories reveal that the type of annealing processes applied in the biphasic none generates different evolution of the rheological data.
- Ressia, Jorge A.,Quinzani, Lidia M.,Valles, Enrique M.,Bello, Pablo,Bello, Antonio
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Read Online
- Design, syntheses and aggregation-induced emission properties of two new enlarged tetraarylethene-based luminogens
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Two new enlarged tetraarylethene-based compounds in which biphenyl and 4,5,9,10-tetrahydropyrene cores connect multiple arylethene units have been synthesized through convenient synthetic procedures. The optical properties and electrochemical properties of the two compounds have been investigated. The two compounds possess high emission efficiency in solid state. Particularly, the absolute fluorescence quantum yield of 4,5,9,10-tetrahydropyrene-cored compound in a solid film is up to 44.1%. The emissions of the two compounds in solutions are very weak but they become strong emitters in solid state or in poor solvents, showing aggregation-induced emission (AIE) characteristics. The two compounds exhibit high thermal stability with Td above 427 °C and show relatively high glass transition temperature with Tg above 142 °C.
- Zhang, Zhao-Ming,Han, Fang-Fang,Zhang, Ran,Li, Nan,Ni, Zhong-Hai
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Read Online
- New Fluorescent Bichromophoric Probes for the Donor-Donor Energy Migration (DDEM) Studies
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Three fluorescent probes were synthesized for studying the excitation energy migration between two identical fluorophores. Each probe has two identical fluorescent groups (dansyl, 7-nitrobenzo-2-oxa-1,3-diazole-4-yl, or fluoresceinyl) linked by the rigid bis-(8-aminooctyl)amide of 4,4′-biphenyldicarbonic acid or flexible dotriacontanedioic acid spacer, which enables the intramolecular energy migration through the distance of 3.2-3.5 nm.
- Johansson,Kalinin,Filatova,Molotkovsky
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Read Online
- Unraveling the Self-Assembly of Heterocluster Janus Dumbbells into Hybrid Cubosomes with Internal Double-Diamond Structure
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Cubosomes are bicontinuous cubic-phase particles generated by amphiphile self-assembly with bicontinuous cubic phases, which creates an intricate network of interconnected nanochannels that endow these materials with special functions for advanced applications. On the other hand, clusters are an attractive class of molecules that exhibit intriguing functions and properties that differ from those of atoms and nanoparticles. Inspired by lipid self-assembly and attracted to the new functionalities of clusters, we prepared special heterocluster Janus dumbbells (HCJDs) composed of dissimilar nanoclusters: namely, a polyoxometalate and a polyhedral oligomeric silsesquioxane. HCJDs resemble conventional amphiphiles and, as such, they self-assemble in solution into faceted hybrid cubosomes via the transformation of vesicles into spongelike aggregates. Multiple mechanisms that lead to equilibrium, including molecular self-assembly, vesicle accumulation, membrane fusion, inner-structure reorganization, and cubic crystal growth, contributed to the overall process. On the basis of these results, we proposed a strategy for self-assembly - from basic molecular design that goes beyond traditional amphiphiles to the construction of micro- or nanomaterials with hierarchical structures and advanced functions.
- Liu, Hong-Kai,Ren, Li-Jun,Wu, Han,Ma, Yong-Li,Richter, Sven,Godehardt, Michael,Kübel, Christian,Wang, Wei
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supporting information
p. 831 - 839
(2019/01/23)
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- A kind of benzene ring - aromatic ring series compound, its preparation method and medical use
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The invention relates to a phenyl ring-aromatic ring cascaded micro-molecular organic compound which can be used as a protein-tyrosine-phosphatase subtype inhibitor and is shown in a general formula I as described in the specification. The compound can be used as a tool compound for research on the biological functions of a variety of subtypes of a protein-tyrosine-phosphatase family in cell signal transduction, so novel means is provided for prevention and treatment of cancers, metabolism and immunological diseases, cardiovascular diseases and nervous diseases. The invention also relates to a preparation method and medicinal application of the compound.
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Paragraph 0145-0148
(2017/12/05)
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- Cp?CoIII-Catalyzed syn-Selective C-H Hydroarylation of Alkynes Using Benzamides: An Approach Toward Highly Conjugated Organic Frameworks
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Hydroarylation of internal alkynes by cost-effective CoIII-catalysis, directed by N-tert-butyl amides, is achieved to avail mono- or dihydroarylated amide products selectively in an atom and step economic way. Several important functional groups were tolerated under the reaction conditions, and syn-hydroarylation products were exclusively isolated. Notably, a 4-fold C-H hydroarylation provided a highly conjugated organic framework in one step. Kinetic study with extensive deuterium labeling experiments were performed to support the proposed mechanism.
- Bera, Sourav Sekhar,Debbarma, Suvankar,Ghosh, Avick Kumar,Chand, Santanu,Maji, Modhu Sudan
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p. 420 - 430
(2017/04/26)
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- Homochiral Metal-Organic Frameworks with Tunable Nanoscale Channel Array and Their Enantioseparation Performance against Chiral Diols
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Enantioseparation is an integral process in the pharmaceutical industry, considering the ever-increasing demand for chiral medicine products. As a new material, porous metal-organic frameworks (MOFs) have shown their potential application in this field because their structures are easy to adjust and control. Though chiral recognition between racemic substrates and frameworks has made preliminary progress, discussions of their size-matching effects are rare. Herein with the help of channel-tunable homochiral MOFs (HMOFs), diols of different sizes have been separated in good enantiomeric excess (ee%). In addition, the ee% reaches 67.4% for the first time for diols as large as 1,1,2-triphenyl-1,2-ethanediol, which turns out to be the most effective value so far.
- Zhuo, Chao,Wen, Yuehong,Hu, Shengmin,Sheng, Tianlu,Fu, Ruibiao,Xue, Zhenzhen,Zhang, Hao,Li, Haoran,Yuan, Jigang,Chen, Xi,Wu, Xintao
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supporting information
p. 6275 - 6280
(2017/06/13)
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- Preparation method of acyl chloride
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The invention relates to a preparation method of acyl chloride. The method comprises the following steps that 1, carboxylic acid is added into a reactor, or carboxylic acid is dissolved in organic solvent, a device is connected, and the temperature is raised to 100 DGE C-250 DEG C; 2, phosgene is introduced into the reactor for a reaction, and then the temperature is decreased to room temperature; 3, nitrogen is introduced, residual phosgene and hydrogen chloride are cleaned away, reaction liquid which is reacted without solvent is subjected to decompression distillation and purification directly, and needed acyl chloride is obtained; reaction liquid which is reacted with the solvent is subjected to decompression distillation to remove the solvent, and needed acyl chloride is obtained. According to the preparation method of acyl chloride, no catalyst is added, the risks that in the synthesizing process, due to the fact that the catalyst is dissolved, color of the finial product of acyl chloride is increased, and the catalyst is remained in late products are avoided, after the reaction is finished, high-quality acyl chloride can be obtained through decompression distillation, and the technological process is simple; due to the fact that in the whole technological process, except for absorbable and available phosgene, hydrogen chloride and carbon dioxide, no other three waste is discharged, the preparation method of acyl chloride is environmentally friendly, and the good implement value is achieved.
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Paragraph 0070; 0071
(2016/11/28)
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- Method of manufacturing imidoyl diazidosulfochloride compd. various compd. and manufacturing method of using the same
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PROBLEM TO BE SOLVED: To provide a new production method for synthesizing an imidoyl chloride compound dispensing with chlorination agents having poor handleability, to provide a method for producing various compounds in high yield and purity by using the imidoyl chloride compound, and to provide a method for isolating the imidoyl chloride compound in high efficiency and purity from a mixture of the imidoyl chloride compound and a phthalic anhydride compound.SOLUTION: The method for producing the imidoyl chloride compound comprises reaction of a specific amide compound with a specific phthaloyl chloride compound to produce a specific imidoyl chloride compound.
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Paragraph 0036
(2016/12/16)
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- Synthesis and biological evaluation of novel bis-aromatic amides as novel PTP1B inhibitors
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A series of bis-aromatic amides was designed, synthesized, and evaluated as a new class of inhibitors with IC50 values in the micromolar range against protein tyrosine phosphatase 1B (PTP1B). Among them, compound 15 displayed an IC50 value of 2.34 ± 0.08 μM with 5-fold preference over TCPTP. More importantly, the treatment of CHO/HIR cells with compound 15 resulted in increased phosphorylation of insulin receptor (IR), which suggested extensive cellular activity of compound 15. These results provided novel lead compounds for the design of inhibitors of PTP1B as well as other PTPs.
- Wang, Wen-Long,Huang, Chao,Gao, Li-Xin,Tang, Chun-Lan,Wang, Jun-Qing,Wu, Min-Chen,Sheng, Li,Chen, Hai-Jun,Nan, Fa-Jun,Li, Jing-Ya,Li, Jia,Feng, Bainian
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supporting information
p. 1889 - 1894
(2014/04/17)
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- Synthesis and polymerization reactions of cyclic imino ethers. VI. Polymers with biphenyl structure
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A monomer of the AB-type and a bifunctional comonomer of the AA-type containing two 2-oxazoline rings and a biphenyl structural unit were prepared from the corresponding carboxylic acids via their esterification and subsequent amidation with an aminoalcohol. The cyclization of an amide to 2-oxazoline structure was achieved by treatment with thionyl chloride followed by liberation of the free base with sodium hydrocarbonate in an aqueous solution. The prepared monomers were used for the polyaddition polymerization of the AB-type monomer having a 2-oxazoline and phenol group bound on adjacent rings of the biphenyl structure in solution. The monomer of the AA-type was used for AA+BB-type polyaddition reactions with aliphatic dicarboxylic acids. Both types of polymerizations have been performed in melt and in solution. The structures of the polymers were determined, and the thermal properties of the polymers were evaluated. Liquid-crystalline (LC) structures of the prepared polymers were observed by DSC measurements and optical microscopy. The polyaddition reactions of the monomers containing a 2-oxazoline ring and a biphenyl unit represent a new efficient way for the preparation of a biphenyl unit containing poly(ether amide)s and poly(ester amide)s.
- Luston, Jozef,Kronek, Juraj,Kleinova, Angela,Janigova, Ivica,Valentova, Helena,Nedbal, Jan
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p. 3936 - 3943
(2012/11/07)
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- New preparation method for Vilsmeier reagent and related imidoyl chlorides
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An environmentally benign and inexpensive preparation method is described of some imidoyl chlorides, including the Vilsmeier reagent (VR), by using phthaloyl dichloride. Synthetic applications were demonstrated using the isolated VR or VR prepared in situ for the transformation of acids to acid chlorides, alcohols to chlorides, and the formylation of dimethylaminobenzene.
- Kimura, Yoshikazu,Matsuura, Daisuke,Hanawa, Takeshi,Kobayashi, Yukimoto
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experimental part
p. 1116 - 1118
(2012/03/26)
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- Bolaamphiphiles bearing bipyridine as mesogenic core: Rational exploitation of molecular architectures for controlled self-assembly
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A bolaamphiphile (5,5-B2NBr8) bearing a functional bipyridine moiety as the mesogenic core is reported for the first time. 5,5-B2NBr8 was found to self-assemble into uniform fibrous structure in aqueous solution, when the concentration was higher than cmc. Analogues of 5,5-B2NBr8 with structural differences in chain length, headgroup, mesogenic core, and substituted position were synthesized, elucidating that small variances of the molecular structure could lead to dramatic changes of the resulting assemblies. For example, compound 4,4-B2NBr8 showed only spherical colloidal aggregates rather than fibers as 5,5-B2NBr8 did, while the only difference between them was the position at which the alkyl chains were attached onto bipyridine. A probable model for the fibrous structure of 5,5-B2NBr8 was proposed. Moreover, exploiting the coordination capacity of bipyridine, assembly and disassembly of 5,5-B2NBr8 could be reversibly controlled through the addition of EDTA and Cu(II), respectively.
- Wu, Guanglu,Verwilst, Peter,Xu, Jun,Xu, Huaping,Wang, Ruji,Smet, Mario,Dehaen, Wim,Faul, Charl F. J.,Wang, Zhiqiang,Zhang, Xi
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scheme or table
p. 5023 - 5030
(2012/06/29)
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- Efficient two directional syntheses of a homophthalate ester and novel resorcylate oligomers
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Thermolysis of 6,6′-(2-oxopropane-1,3-diyl)bis(2,2-dimethyl-4H-1,3- dioxin-4-one) in the presence of methanol gave a triketo-ester which subsequently aromatized to provide a synthetically useful homophthalate ester. Enolate C-acylation in the presence of diethylzinc was used to synthesize other double diketo-dioxinones, which on cyclization, aromatization and dioxinone ring opening gave novel double resorcylate derivatives.
- Patel, Bhavesh H.,Heath, Scott F.A.,Mason, Andrew M.,Barrett, Anthony G.M.
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supporting information; experimental part
p. 2258 - 2261
(2011/05/05)
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- Nesting complexation of C60 with large, rigid D2 symmetrical macrocycles
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A series of four chiral D2 symmetrical macrocycles, in which two 3,3′-disubstituted Binol units are bridged by conjugated organic spacers of differing lengths and/or electronic properties, have been synthesized and characterized. The four different bridges consist of either ether or ester linkages in combination with either short biphenyl spacers or long diethynylphenyl spacers. NMR, CD spectroscopy, and molecular modeling help rationalize the shape of the cyclic scaffolds and even subtle modifications in the bridging units lead to drastic changes in conformation. The three macrocycles with longer bridging units and/or ester linkages form stable 1:1 complexes with C60 in toluene. The one with a short spacer and ether linkage does not. The binding constants have been determined with a high degree of accuracy via equilibrium-restricted factor analysis; with long spacers and ester linkages log Ka = 4.37(2); with short spacers and ester linkages log Ka = 3.498(4); with long spacers and ether linkages log Ka = 3.509(2). The Royal Society of Chemistry 2010.
- Caricato, Marco,Coluccini, Carmine,Dondi, Daniele,Vander Griend, Douglas A.,Pasini, Dario
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experimental part
p. 3272 - 3280
(2010/08/21)
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- Cyclization of propargylic amides: Mild access to oxazole derivatives
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The substrate scope, the mechanistic aspects of the gold-catalyzed oxazole synthesis, and substrates with different aliphatic, aromatic, and functional groups in the side chain were investigated. Even molecules with several propargyl amide groups could easily be converted, delivering di- and trioxazoles with interesting optical properties. Furthermore, the scope of the gold(I)-catalyzed alkylidene synthesis was investigated. Further functionalizations of these isolable intermediates of the oxazole synthesis were developed and chelate ligands can be obtained. The use of Barluenga's reagent offers a new and mild access to the synthetically valuable iodoalkylideneoxazoles from propargylic amides, this reagent being superior to other sources of halogens.
- Weyrauch, Jan P.,Hashmi, A. Stephen K.,Schuster, Andreas,Hengst, Tobias,Schetter, Stefanie,Littmann, Anna,Rudolph, Matthias,Hamzic, Melissa,Visus, Jorge,Rominger, Frank,Frey, Wolfgang,Bats, Jan W.
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supporting information; experimental part
p. 956 - 963
(2010/06/12)
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- Synthesis and properties of luminophores derived from fluorinated biphenyls
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A procedure was developed for the synthesis of dimethyl 2-fluoro-and 2,2′-difluorobiphenyl-4,4′-dicarboxylates. The latter were converted into fluorinated 4,4′-bis[(E)-2-(1,3-benzoxazol-2-yl)ethenyl]-and 4,4′-bis[5-(4-octyloxyphenyl)-1,3,4-oxadiazol-2-yl]biphenyls which showed strong luminescence in the crystalline state and in solution; their spectral properties were examined.
- Ol'khovik,Pap,Vasilevskii,Galinovskii,Tereshko
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experimental part
p. 1172 - 1179
(2009/09/25)
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- Gallotannins and ellagitannins as regulators of cytokine release
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A means and method for increasing or inhibiting the secretion of cytokines using gallotannins and ellagitannins is described. The preferred cytokine release inhibiting compounds are dimeric gallotannins having a linker molecule that misaligns the carbohydrate cores of the compounds. The preferred cytokine release promoting gallotannins and ellagitannins include a diaryl ether linker unit. In comparison to the more structurally complex ellagitannins, the compounds of this invention are structurally simpler, easier to synthesize, and more potent.
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Page/Page column 19; 40; 41
(2010/11/28)
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- 6-monoacetylmorphine derivatives useful in immunoassay
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Analogs of 6-monoacetyl morphine (6-MAM) are described. These include analogs derivatized at either the C-3 position, the C-6 position, or the nor position of the molecule. These analogs allow for elaboration with linkers terminated by a functional group such as an activated ester, the functional groups being useful for attaching the molecule to other entities such as proteins, polysaccharides, and reporter groups.
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Page/Page column 10
(2010/11/28)
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- 6-Monoacetylmorphine derivatives useful in immunoassay
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Analogs of 6-monoacetyl morphine (6-MAM) are described. These include analogs derivatized at either the C-3 position, the C-6 position, or the nor position of the molecule. These analogs allow for elaboration with linkers terminated by a functional group such as an activated ester, the functional groups being useful for attaching the molecule to other entities such as proteins, polysaccharides, and reporter groups.
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- Synthesis and characterization of new blue light emitting poly(arylenevinylene) derivatives containing fluorene pendant
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New poly(arylenevinylene) derivatives composed of biphenyl or terphenyl units in the main chain and fluorene pendant groups are synthesized by Yamamoto coupling reaction or Suzuki coupling reaction. The obtained polymers showed high color pure blue emission due to controlled conjugation length and inhibited intermolecular interaction as well as high solubility and good thermal stability.
- Kim, Yun-Hi,Jung, Sang-Yun,Kwon, Soon-Ki
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p. 169 - 176
(2007/10/03)
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- Preparative synthesis of functionally substituted esters of dehydroabietic and 4,4′-biphenyldicarboxylic acids
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A preparative synthesis of functionally substituted esters of dehydroabietic and 4,4′-biphenylcarboxylic acids by the reaction of chlorides of these acids with alcohols in the presence of pyridine is developed. 4,4′-Biphenyldicarbonyl dichloride reacts with hydroperoxides to form peroxy esters and with lithium alcoholates, which allows preparation of the corresponding ethers derived from secondary and tertiary alcohols. 2004 MAIK "Nauka/Interperiodica".
- Dikusar,Yuvchenko,Kozlov,Ol'khovik,Potkin
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p. 1259 - 1263
(2007/10/03)
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- In vitro and in vivo inhibition of LPS-induced tumor necrosis factor-α production by dimeric gallotannin analogues
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Designed dimeric gallotannin analogues featuring two tetragalloylglucopyranose cores connected by various hydrocarbon linkers inhibit tumor necrosis factor-α secretion from lipopolysaccharide-stimulated human peripheral blood mononuclear cells by up to 53% (5-24 μM concentration range) compared to control. Comparable suppression of tumor necrosis factor-α levels (~50% vs control) was observed in the plasma of rats co-treated with lipopolysaccharide and specific tannin analogues selected for their lack of interleukin 1-β stimulating activity. Copyright
- Feldman, Ken S,Wilson, Sarah L,Lawlor, Michael D,Lang, Charles H,Scheuchenzuber, William J
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- Noncovalent binding of sensitizers for lanthanide(III) luminescence in an EDTA-bis(β-cyclodextrin) ligand
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EDTA-linked β-cyclodextrin dimer 3 was synthesized from EDTA bis(anhydride) 1 and mono-(propylamino)-appended β-cyclodextrin 2. p-tert-Butylbenzoate 5, bound by the β-cyclodextrin cavities of 3 with an association constant of 104 M-1 in water, acts as a sensitizer for the EuIII and TbIII complexes of 3. Luminescence spectroscopy, microcalorimetry, and GdIII-induced NMR relaxation rate measurements prove that 3 forms a 1:2 complex with 5 and that one of the β-cyclodextrin-bound sensitizers coordinates to the EDTA-encapsulated LnIII ion. The EuIII complex of 3 forms strong 1:1 complexes (K ≈ 107 M-1) with bis(propylamido adamantyl)-functionalized biphenyl sensitizers 7 and 8 in water. Both β-cyclodextrins of 3 are involved in the binding of these guests. The amide functionality adjacent to the biphenyl unit in 7 and 8 coordinates to the EDTA-encapsulated LnIII ion. For these biphenyl-based antennae both binding to β-cyclodextrin and coordination to the LnIII center are crucial for efficient sensitization.
- Michels, Jasper J.,Huskens, Jurriaan.,Reinhoudt, David N.
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p. 2056 - 2064
(2007/10/03)
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- Synthesis of a novel antiferroelectric liquid crystal: Influence of biphenyl ester linkages on magnitude of spontaneous polarization
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A novel AFLC compound, (S)-4-dodecyloxyphenyl-4-(2-methyl)-butyloxybiphenyldicarboxylate (DPMBBD), has been synthesized and its liquid crystalline behaviour is studied by thermal microscopy (TM), Diffrential Scanning Calorimetry (DSC), spontaneous polarization (Ps) and response times (τ) measurements. The preliminary investigations on the ferroelectric properties of the present material imply the presence of an antiferroelectric phase (Sm-CA*) with a high magnitude of spontaneous polarization. Further, the molecular contributions towards the magnitude of spontaneous polarization in the antiferroelectric phase are discussed in the light of ester linkages of biphenyl moiety.
- Kumar, Poluri A.,Pisipati, Venkata G.K.M.
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p. 161 - 170
(2007/10/03)
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- Design and synthesis of a novel wing shaped achiral antiferroelectric liquid crystal
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A novel wing shaped achiral antiferroelectric liquid crystalline compound, 1,3-phenylene bis-[phenylene-1-biphenyldicarboxylato)-3-(4-n-tetradecyloxybenzoyl)biphenyl dicarboxylate] (abbreviated as PBPBTB), having 1,3-phenylene [4-biphenyldicarboxylate-(4-n-tetradecyloxy benzoate)] units as wings, has been synthesized while its liquid crystalline behaviour is characterized by thermal microscopy (TM), differential scanning calorimetry (DSC), spontaneous polarization (Ps) and response times (τ) studies. The preliminary investigations on the ferroelectric properties of the present material show the presence of an antiferroelectric phase.
- Kumar,Pisipati
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p. 147 - 160
(2007/10/03)
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- Immunoassay for LSD and 2-oxo-3-hydroxy-LSD
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The present invention provides hapten derivatives useful for the preparation of antigens, antibodies and reagents for use in immunoassays for the detection of LSD and 2-oxo-3-hydroxy LSD. In the present invention, the 2-oxy LSD nucleus is derivatized out of the indole nitrogen to form an aminoalkyl derivative. The resulting haptens can then be further modified at this functionalized position for linking to appropriate immunogenic or labeling groups to provide reagents for immunoassays having substantially equal specificity for both LSD and 2-oxo-3-hydroxy-LSD.
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- Synthesis and magnetic properties of some crystalline nitroxide radicals
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The syntheses of different nitroxide radicals are reported. The thermal behaviour of the nitroxide radicals was examined by polarizing microscopy, differential scanning calorimetry as well as X-ray diffraction experiments. Temperature dependent magnetic susceptibility measurements were carried out in order to determine the magnetic properties of these nitroxide radicals. The majority of the radicals presented here show weak antiferromagnetic exchange interactions.
- Griesar,Soto-Bustamante,Haase
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p. 567 - 575
(2007/10/03)
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- Reagents for lysergic acid diethylamide immunoassay
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The present invention provides hapten derivatives that are useful for the preparation of antigens, antibodies and reagents having superior performance characteristics for use in immunoassays for the detection of LSD and nor-LSD. In the present invention the LSD nucleus is derivatized out of the indole nitrogen to form an aminoalkyl derivative. Derivatives have also been synthesized out of the piperidine nitrogen of the LSD nucleus. The resulting haptens can then be further modified at these functionalized positions for linking to appropriate antigenic or labelling groups to provide reagents for LSD immunoassays having excellent sensitivity and selectivity for both LSD and nor-LSD.
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- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 16. Model studies for the construction of conjugated polymers
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Reaction of a range of bis(ylides) with acid chlorides has been used to prepare the bis(oxoylides) 11-15. Similarly a range of simple ylides react with bis(acid chlorides) to give bis(oxoylides) 19-27 with the isomeric structure. Flash vacuum pyrolysis (FVP) of one example of the first type results in extrusion of Ph3P rather than the expected Ph3PO while six examples of the second type do extrude Ph3PO upon FVP at 500 °C to afford the bis(alkynes) 28. Examples of the corresponding bis(tributylphosphonium ylides) have also been prepared but attempts to construct a tetrakis(oxoylide) 31 using a stepwise approach were unsuccessful. Fully assigned 13C NMR spectra are presented for six of the bis(oxoylides).
- Aitken, R. Alan,Drysdale, Martin J.,Hill, Lawrence,Lumbard, Keith W.,Maccallum, James R.,Seth, Shirley
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p. 11039 - 11050
(2007/10/03)
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- Liquid crystal compound
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The novel liquid crystal compounds of the present invention are represented by the following formulas ?I!-?II! and have tristable molecular orientation states and can be used for display devices and electrooptical devices. STR1 wherein R1 represents an alkyl group of 5-18 carbon atoms; R2 represents an alkyl group of 6-16 carbon atoms; R3 represents an alkyl group of 8-18 carbon atoms; R4 represents an alkyl group of 6-14 carbon atoms; Y represents STR2 and * indicates an optically active center.
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- Liquid crystal compounds
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Antiferroelectric liquid crystal compounds are provided which have the formula STR1 wherein R1 represents an alkyl group having 5-18 carbon atoms, R2 represents an alkyl group having 6-16 carbon atoms, Y represents a group STR2 and A represents a group STR3
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- Thermochromic mixtures
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The invention relates to thermochromic liquid crystalline phases with at least two components, characterized in that at least one component is an optically active compound of the formula I STR1 wherein R1 and R2 are each independently a chiral residue, importing to the phase a tight helical twist. STR2 denotes a 1,4-phenylene group optionally substituted by fluorine, X1 and X2 are each independently O or NH, n is 1, 2 or 3 and m is 0 or 1, which can be used in electro-optic devices, in temperature indicating devices or for color-changing cosmetics.
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- An improved acid chloride preparation via phase transfer catalysis
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Phase transfer catalysis has been found to be effective for the rapid conversion of carboxylic acids in high yield to the corresponding acid chlorides. The procedure is well suited for acids that exhibit low solubilities in normal organic solvents.
- Burdett
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p. 441 - 442
(2007/10/02)
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- Molecular recognition in the solid state: Controlled assembly of hydrogen-bonded molecular sheets
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A novel hydrogen-bonding motif for the control of solid-state structures has been developed. The motif is based on the hydrogen bonding complementarity of carboxylic acids with 2-aminopyridine derivatives. Linking two aminopyridine groups through a rigid aromatic spacer provides a receptor unit that can complex dicarboxylic acids. When there is a good correspondence between the length of the spacer and that of the carboxylic acid, a discrete 1:1 complex is formed. When the dicarboxylic acid is longer than the receptor, an alternating hydrogen-bonded cocrystal occurs with the carboxylates on each diacid binding to different receptors. This motif dominates the cocrystal, forming even when the relative lengths of the diacid and the receptor change. Within the constraints of the alternating ribbon structure, the spatial position of the two components can be varied in a well-defined and predictable manner.
- Garcia-Tellado, Fernando,Geib, Steven J.,Goswami, Shyamaprosad,Hamilton, Andrew D.
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p. 9265 - 9269
(2007/10/02)
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- Palladium-Catalyzed Reductive Coupling of Aromatic Acid Dichlorides with Disilanes
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Electron-deficient aromatic acid-chlorides are converted to biphenyl compounds by palladium-catalyzed reaction with disilanes.
- Krafft, Terry E.,Rich, Jonathan D.,McDermott, Philip J.
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p. 5430 - 5432
(2007/10/02)
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- Synthesis and Thermal Transitions of Some Liquid Crystalline Oligomers
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Fourteen aromatic ester oligomers have been synthesised, the majority of which have not been described previously.They can be considered as model compounds for liquid crystalline polyesters, and as such give useful information regarding the relationship between chemical structure and thermal properties.Such oligomers are also potentially important as precursors to liquid crystalline monomers.
- Chan, W.-C.,Mooney, J. A.,Windle, A. H.
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