- Understanding the remarkable difference in liquid crystal behaviour between secondary and tertiary amides: The synthesis and characterisation of new benzanilide-based liquid crystal dimers
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A number of liquid crystal dimers have been synthesised and characterised containing secondary or tertiary (N-methyl) benzanilide-based mesogenic groups. The secondary amides all form nematic phases, and we present the first example of an amide to show the twist-bend nematic (NTB) phase. Only two of the correspondingN-methylated dimers formed a nematic phase and with greatly reduced nematic-isotropic transition temperatures. Characterisation using 2D ROESY NMR experiments, DFT geometry optimisation and X-ray diffraction reveal that there is a change in the preferred conformation of the benzanilide core on methylation, fromZtoE. The rotational barrier around the N-C(O) bond has been measured using variable temperature1H NMR spectroscopy. This dramatic change in shape accounts for the remarkable difference in liquid crystalline behaviour between these secondary and tertiary amide-based materials.
- Strachan, Grant J.,Harrison, William T. A.,Storey, John M. D.,Imrie, Corrie T.
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- 4′-(2H-tetrazol-5-yl)-[1,1′-biphenyl]-4-carboxylic acid: Synthetic approaches, single crystal X-ray structures and antimicrobial activity of intermediates
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Two synthetic approaches towards 4′-(2H-tetrazol-5-yl)-[1,1′-biphenyl]-4-carboxylic acid, a valuable organic ligand for the preparation of metal-organic frameworks, are reported. The first reaction sequence leading to the target compound comprises the iod
- Ardeleanu, Rodinel,Dasc?lu, Andrei,Shova, Sergiu,Nicolescu, Alina,Ro?ca, Irina,Bratanovici, Bogdan-Ionel,Lozan, Vasile,Roman, Gheorghe
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- Amplification of Elementary Surface Reaction Steps on Transition Metal Surfaces Using Liquid Crystals: Dissociative Adsorption and Dehydrogenation
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Elementary reaction steps, including adsorption and dissociation, of a range of molecular adsorbates on transition metal surfaces have been elucidated in the context of chemical catalysis. Here we leverage this knowledge to design liquid crystals (LCs) supported on ultrathin polycrystalline gold films (predominant crystallographic face is (111)) that are triggered to undergo orientational transitions by dissociative adsorption and dehydrogenation reactions involving chlorine and carboxylic acids, respectively, thus amplifying these atomic-scale surface processes in situ into macroscopic optical signals. We use electronic structure calculations to predict that 4′-n-pentyl-4-biphenylcarbonitrile (5CB), a room temperature nematic LC, does not bind to Au(111) in an orientation that changes upon dissociative adsorption of molecular chlorine, a result validated by experiments. In contrast, 4-cyano-4-biphenylcarboxylic acid (CBCA) is calculated to bind strongly to Au(111) in a perpendicular orientation via dehydrogenation of the carboxylic acid group, which we confirmed using polarization-modulation infrared reflection-absorption spectroscopy. A maximum coverage of 0.07 monolayer of CBCA on the gold surface is sufficient to cause a perpendicular orientation of the LC. Dissociative adsorption of Cl2 gas on the gold surface, resulting in 0.5 monolayer coverage of Cl, displaces CBCA from Au(111) and thus triggers a strikingly visible change in orientation of the LC. Infrared spectroscopy established the orientation of adsorbed CBCA to be parallel to the Cl covered surface, with the COOH plane perpendicular to the surface, as predicted by first-principles calculations. These results demonstrate the use of first-principles calculations and transition metal surfaces to design LCs that report in situ targeted atomic-scale surface processes.
- Yu, Huaizhe,Szilvási, Tibor,Wang, Kunlun,Gold, Jake I.,Bao, Nanqi,Twieg, Robert J.,Mavrikakis, Manos,Abbott, Nicholas L.
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- Improving the metabolic stability of antifungal compounds based on a scaffold hopping strategy: Design, synthesis, and structure-activity relationship studies of dihydrooxazole derivatives
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L-amino alcohol derivatives exhibited high antifungal activity, but the metabolic stability of human liver microsomes in vitro was poor, and the half-life of optimal compound 5 was less than 5 min. To improve the metabolic properties of the compounds, the scaffold hopping strategy was adopted and a series of antifungal compounds with a dihydrooxazole scaffold was designed and synthesized. Compounds A33-A38 substituted with 4-phenyl group on dihydrooxazole ring exhibited excellent antifungal activities against C. albicans, C. tropicalis and C. krusei, with MIC values in the range of 0.03–0.25 μg/mL. In addition, the metabolic stability of compounds A33 and A34 in human liver microsomes in vitro was improved significantly, with the half-life greater than 145 min and the half-life of 59.1 min, respectively. Moreover, pharmacokinetic studies in SD rats showed that A33 exhibited favourable pharmacokinetic properties, with a bioavailability of 77.69%, and half-life (intravenous administration) of 9.35 h, indicating that A33 is worthy of further study.
- Cheng, Maosheng,Su, Xin,Sun, Nannan,Sun, Yin,Tian, Linfeng,Yin, Wenbo,Zhang, Chu,Zhao, Dongmei,Zhao, Liyu,Zhao, Shizhen,Zheng, Yang
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- Lead discovery, chemical optimization, and biological evaluation studies of novel histone methyltransferase SET7 small-molecule inhibitors
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The post-translational modifications of histones, including histone methylation and demethylation, control the expression switch of multiple genes. SET domain-containing lysine methyltransferase 7 (SET7) is the only methyltransferase, which can specifically monomethylate lysine-4 of histone H3 (H3K4me1) and play critical roles in various diseases, including breast cancer, hepatitis C virus (HCV), atherosclerotic vascular disease, diabetes, prostate cancer, hepatocellular carcinoma, and obesity. However, several known SET7 inhibitors exhibit weak activity or poor selectivity. Therefore, the development of novel SET7 inhibitors is highly desirable and of great clinical value. In this study, we identified 2–79 as a new hit compound by structure-based virtual screening and further AlphaLISA-based biochemical evaluation. Via chemical optimization, the synthesized compound DC21 was confirmed as a potent SET7 inhibitor with an IC50 value of 15.93 μM. The interaction between DC21 and SET7 was also validated through SPR experiment. Especially, DC21 retarded proliferation of MCF7 cells with an IC50 value of 25.84 μM in cellular level. In addition, DC21 has good selectivity for several other epigenetic targets, such as SUV39H1, G9a, NSD1, DOT1L and MOF. DC21 can serve as a lead compound to develop more potential SET7 inhibitors and as a chemical probe for SET7 biological function studies.
- Cao, Liyuan,Ding, Hong,Han, Jie,Hou, Zeng,Li, Yuanqing,Luo, Cheng,Min, Wenjian,Niu, Ao,Yang, Peng,Zhang, Rukang
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- Thioether-linked liquid crystal dimers and trimers: The twist-bend nematic phase
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Systematic synthesis of thioether-linked dimers and trimers was carried out to reveal molecular designs for inducing mesophases and twist-bend nematic (NTB) phases. A five-fold approach based on molecular structural parameters including the ter
- Arakawa, Yuki,Komatsu, Kenta,Inui, Satoyoshi,Tsuji, Hideto
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- Magnetite tethered mesoionic carbene-palladium (II): An efficient and reusable nanomagnetic catalyst for Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions in aqueous medium
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In this paper, a highly active, air- and moisture-stable and easily recoverable magnetic nanoparticles tethered mesoionic carbene palladium (II) complex (MNPs-MIC-Pd) as nanomagnetic catalyst was successfully synthesized by a simplistic multistep synthesis under aerobic conditions using commercially available inexpensive chemicals for the first time. The synthesized MNPs-MIC-Pd nanomagnetic catalyst was in-depth characterized by numerous physicochemical techniques such as FT-IR, ICP-AES, FESEM, EDS, TEM, p-XRD, XPS, TGA and BET surface area analysis. The prepared MNPs-MIC-Pd nanomagnetic catalyst was used to catalyze the Suzuki–Miyaura and Mizoroki–Heck cross-coupling reactions and exhibited excellent catalytic activity for various substrates under mild reaction conditions. Moreover, MNPs-MIC-Pd nanomagnetic catalyst could be easily and rapidly recovered by applying an external magnet. The recovered MNPs-MIC-Pd nanomagnetic catalyst exhibited very good catalytic activity up to ten times in Suzuki–Miyaura and five times in Mizoroki–Heck cross-coupling reactions without considerable loss of its catalytic activity. However, MNPs-MIC-Pd nanomagnetic catalyst shows notable advantages such as heterogeneous nature, efficient catalytic activity, mild reaction conditions, easy magnetic work up and recyclability.
- Kempasiddhaiah, Manjunatha,Kandathil, Vishal,Dateer, Ramesh B.,Sasidhar, Balappa S.,Patil, Shivaputra A.,Patil, Siddappa A.
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- Palladium-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of amides by carbon-nitrogen bond activation
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Palladium-catalyzed Suzuki-Miyaura cross-coupling or aryl halides is widely employed in the synthesis of many important molecules in synthetic chemistry, including pharmaceuticals, polymers and functional materials. Herein, we disclose the first palladium-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of amides for the synthesis of biaryls through the selective activation of the N-C(O) bond of amides. This new method relies on the precise sequence engineering of the catalytic cycle, wherein decarbonylation occurs prior to the transmetallation step. The reaction is compatible with a wide range of boronic acids and amides, providing valuable biaryls in high yields (>60 examples). DFT studies support a mechanism involving oxidative addition, decarbonylation and transmetallation and provide insight into high N-C(O) bond activation selectivity. Most crucially, the reaction establishes the use of palladium catalysis in the biaryl Suzuki-Miyaura cross-coupling of the amide bond and should enable the design of a wide variety of cross-coupling methods in which palladium rivals the traditional biaryl synthesis from aryl halides and pseudohalides.
- Zhou, Tongliang,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 9865 - 9871
(2019/11/11)
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- PYRROLIDINE OR THIAZOLIDINE CARBOXYLIC ACID DERIVATIVES, PHARMACEUTICAL COMPOSITION AND METHODS FOR USE IN TREATING METABOLIC DISORDERSAS AS AGONISTS OF G- PROTEIN COUPLED RECEPTOR 43 (GPR43)
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The present invention is directed to novel compounds of formula (I) and their use in treating and/or preventing metabolic diseases.
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Page/Page column 203
(2011/07/07)
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- Substituted pyridoxines as anti-platelet agents
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Compounds with antiplatelet aggregation characteristics for the treatment of cardiovascular and cardiovascular related disease, are described. The methods are directed to administering pharmaceutical compositions comprising a pyridoxine analogue.
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Page/Page column 14
(2008/06/13)
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- Design, synthesis, and SAR of anthranilamide-based factor Xa inhibitors incorporating substituted biphenyl P4 motifs
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Anthranilamides 4 and 5 were designed and synthesized as selective and orally bioavailable factor Xa inhibitors. Structural modifications aimed at lowering their lipophilicity were performed at the central phenyl ring and at the S4 binding biphenyl region by incorporating water solublizing substituents. The resulting compounds (e.g., 7, 8, 14, 30a, and 32b) are highly potent in vitro, and show improved activity in human plasma-based thrombin generation assay.
- Zhang, Penglie,Bao, Liang,Zuckett, Jingmei F.,Goldman, Erick A.,Jia, Zhaozhong J.,Arfsten, Ann,Edwards, Susan,Sinha, Uma,Hutchaleelaha, Athiwat,Park, Gary,Lambing, Joseph L.,Hollenbach, Stanley J.,Scarborough, Robert M.,Zhu, Bing-Yan
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p. 983 - 987
(2007/10/03)
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- Fibrinogen receptor antagonists
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Novel fibrinogen receptor antagonists of the formula: are provided in which the claimed compounds exhibit fibrinogen receptor antagonist activity, inhibit platelet aggregation and are therefore useful in modulating thrombus formation.
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- NMR-based discovery of lead inhibitors that block DNA binding of the human papillomavirus E2 protein
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The E2 protein is required for the replication of human papillomaviruses (HPVs), which are responsible for anogenital warts and cervical carcinomas. Using an NMR-based screen we tested compounds for binding to the DNA-binding domain of the HPV-E2 protein. Three classes of compounds were identified which bound to two distinct sites on the protein. Biphenyl and biphenyl ether compounds containing a carboxylic acid bind to a site near the DNA recognition helix and inhibit the binding of E2 to DNA. Benzophenone- containing compounds which lack a carboxylic acid group bind to the β- barrel formed by the dimer interface and exhibit negligible effects on the binding of E2 to DNA. Structure-activity relationships from the biphenyl and biphenyl ether compounds were combined to produce a compound [5-(3'- (3'',5''-dichlorophenoxy)-phenyl)-2,4-pentadienoic acid] with an IC50 value of approximately 10 μM. This compound represents a useful lead for the development of antiviral agents that interfere with HPV replication and further illustrates the usefulness of the SAR by NMR method in the drug discovery process.
- Hajduk, Philip J.,Dinges, Jürgen,Miknis, Gregory F.,Merlock, Megan,Middleton, Tim,Kempf, Dale J.,Egan, David A.,Walter, Karl A.,Robins, Terry S.,Shuker, Suzy B.,Holzman, Thomas F.,Fesik, Stephen W.
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p. 3144 - 3150
(2007/10/03)
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- The Effects of Substituents on the Rate of Saponification of Biphenyl-4-carboxylates
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Second-order rate constants have been measured for the saponification of methyl 2'-, 3'-, and 4'-substituted biphenyl-4-carboxylates at several temperatures in 85percent (w/w) methanol-water and activation parameters have been calculated.The Hammett equation applies very well to the saponification of 3'- and 4'-substituted biphenyl-4-carboxylates with ?-constants evaluated by the FMMF method.The effect of 2'-substituents is understandable in terms of ?-electron steric effects.
- Ananthakrishnanadar, Ponnambalanad.,Kannan, Nagarathnam
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