- Facile synthesis of new quinoxalines from ethyl gallate by green chemistry protocol
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Efficient synthesis of quinoxalines from gallic acid ethyl ester is reported for the first time in this study. The results show the production of three heterocyclic amines instead of the amides expected from aminolysis reactions. Ethyl 8-hydroxy-1,2,3,4-tetrahydroquinoxaline-6-carboxylate G-A1, ethyl 2,3,6,7-tetrahydro-1H,5H-pyrazino[1,2,3-de]quinoxaline-9-carboxylate G-A2, and ethyl 8-hydroxy-4-(2-hydroxyethyl)-1,2,3,4-tetrahydroquinoxaline-6-carboxylate G-A3 were obtained with 97, 92, and 95% yield, respectively, after 30?min of reaction at 65?°C and 400?rpm using ethanol as a solvent.
- Lima, Rafaely N.,Porto, André L.M.
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Read Online
- The effect of solvent composition on grafting gallic acid onto chitosan via carbodiimide
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The primary antioxidant (AOX) activity of chitosan can be introduced by grafting of phenolic compound - gallic acid (GA) to its amino and/or hydroxyl groups. The objective of this study was to investigate the effect of ethanol (EtOH) concentration (0%, 25%, 50%, and 75% in water) on efficiency of grafting GA onto chitosan in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS). The grafting was confirmed by FTIR and the efficiency was quantified as Folin's total phenolics. When pure deionized water was used as a sole solvent (0% EtOH), GA was grafted to chitosan at the largest extent (285.9 mg GA/g chitosan). As the concentration of EtOH increased, the grafting efficiency proportionally decreased. NMR studies showed that EtOH inhibited grafting of GA by prohibiting the production of the intermediate - NHS ester. The results confirm that the concentration of EtOH in grafting solution significantly affects grafting efficiency of GA on chitosan.
- Guo, Ping,Anderson, John D.,Bozell, Joseph J.,Zivanovic, Svetlana
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Read Online
- Two asymmetrical perylene diimide derivatives: Synthesis, optical-electrochemical properties and morphologies of self-assembly
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Perylene diimides (PDIs) belong to an important class of photoactive materials due to their excellent electrical and photophysical properties. Highly controlled aggregation and self-assembly attributed to the large π-conjugated aromatic scaffold have led to a variety of optoelectronic applications. In this manuscript, two PDI derivatives PDI-1 and PDI-2 with unsymmetrical N-substitution of amine and ester-bridge were designed and synthesized. These two compounds were characterized by NMR, Fourier transform infrared (FT-IR), and high-resolution mass spectrometry (HRMS). The photophysical properties were studied by UV–Vis absorption and fluorescence spectroscopy. Cyclic voltammograms of PDI-1 and PDI-2 were investigated and HOMO and LUMO energy levels of both two PDIs were estimated as ?6.2 and ?3.9 ?eV, respectively. Thermal properties were also studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). PDI-1 was assembled into nanotubes while PDI-2 was assembled into nanobelts respectively, via a reprecipitation method. PDI-1 and PDI-2 show good potential application in organic devices such as solar cells, organic field-effect transistors (OFETs) and so on.
- Liu, Jian,Song, Yuting,Tao, Jiayu,Xu, Hai-Jun,Zhang, Jiuxuan
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- Method for producing ester based on eco-friendly and high efficiency esterification by using base exchange of salt and the compound thereof
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The present invention relates to an esterification reaction-based eco-friendly and high efficiency ester compound using ion exchange and an ester compound thereof. The esterification generally proceeds by reverse reaction with water, resulting in poor yield of the ester. In order to avoid hydrolysis, the esterification reaction was environmentally or non-limited due to the continuous supply of hydrochloric acid gas or the use of chlorinated thionyl chloride as a noxious substance. To the present invention, a continuous hydrochloric acid gas is provided by ion exchange of a salt, and magnesium sulfate acts as a dehydrating agent to remove water generated in esterification. In addition, the reactants are cheap and the product is also low in harmfulness and easier to handle and thus more efficient reaction is possible.
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Paragraph 0099-0105; 0107
(2021/07/07)
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- Design, Synthesis, and Antifungal Activity of Alkyl Gallates Against Plant Pathogenic Fungi In Vitro and In Vivo
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A series of alkyl gallates was synthesized by reacting gallic acid with the corresponding alcohols. Their structures were determined on the basis of spectroscopic data, including NMR and MS. The antifungal activities of these compounds against plant pathogenic fungi in vitro and in vivo were assessed.
- Zhao, Xiao-Long,Li, Chun-Qing,Song, Xiao-Mei,Yan, Shuang-Mei,Luo, Du-Qiang
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- Polyhydroxybenzoic acid derivatives as potential new antimalarial agents
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With more than 200 million cases and 400,000 related deaths, malaria remains one of the deadliest infectious diseases of 2021. Unfortunately, despite the availability of efficient treatments, we have observed an increase in people infected with malaria since 2015 (from 211 million in 2015 to 229 million in 2019). This trend could partially be due to the development of resistance to all the current drugs. Therefore, there is an urgent need for new alternatives. We have, thus, selected common natural scaffolds, polyhydroxybenzoic acids, and synthesized a library of derivatives to better understand the structure–activity relationships explaining their antiplasmodial effect. Only gallic acid derivatives showed a noticeable potential for further developments. Indeed, they showed a selective inhibitory effect on Plasmodium (IC50 ~20 μM, SI > 5) often associated with interesting water solubility. Moreover, this has confirmed the critical importance of free phenolic functions (pyrogallol moiety) for the antimalarial effect. Methyl 4-benzoxy-3,5-dihydroxybenzoate (39) has, for the first time, been recognized as a potential lead for future research because of its marked inhibitory activity against Plasmodium falciparum and its significant hydrosolubility (3.72 mM).
- Degotte, Gilles,Francotte, Pierre,Pirotte, Bernard,Frédérich, Michel
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- Influence of functional groups on the self-assembly of liquid crystals
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Functional groups in the molecule play an important role in the molecular organization process. To reveal the influence of functional groups on the self-assembly at interface, herein, the self-assembly structures of three liquid crystal molecules, which only differ in the functional groups, are explicitly characterized by using scanning tunneling microscopy (STM). The high-resolution STM images demonstrate the difference between the supramolecular assembly structures of three liquid crystal molecules, which attribute to the hydrogen bonding interaction and π-π stacking interaction between different functional groups. The density functional theory (DFT) results also confirm the influence of these functional groups on the self-assemblies. The effort on the self-assembly of liquid crystal molecules at interface could enhance the understanding of the supramolecular assembly mechanism and benefit the further application of liquid crystals.
- Tan, Shanchao,Tao, Jiayu,Luo, Wendi,Jiang, Hao,Liu, Yuhong,Xu, Haijun,Zeng, Qingdao,Shi, Hongyu
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supporting information
p. 1149 - 1152
(2020/10/12)
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- Exceptional dual fluorescent, excited-state intramolecular proton-transfer (ESIPT) columnar liquid crystals characterized by J-stacking and large Stokes shifts
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Excited-State Intramolecular Proton-Transfer (ESIPT) fluorophores are emerging as promising future materials for electronic and biotechnological applications. ESIPT columnar (Col) liquid crystals (LCs) have been especially projected as the apt materials for advanced technological endeavors. But, there are hardly any explorations in this direction and thus, needing immediate attention. Herein we report on the synthesis, characterization, and ESIPT activity of a homologous series of novel phasmidic bis(N-salicylideneaniline) Col LCs. Optical microscopic, calorimetric and powder X-ray diffraction (XRD) studies evidence the occurrence of hexagonal columnar (Colh) phase having p6mm symmetry where the constituent slices result from the self-assembly of a pair of mesogens in a side-by-side manner facilitated by intense longitudinal π-π interactions. X-ray data confirm the absence of both directionally correlated tilting of the slices and transverse core-core interactions within the columns. Fluorescence probing clearly evidence the ESIPT occurring not only in DCM solution of the mesogens but also in their three-condensed states viz., solid, liquid crystal, and isotropic liquid phase; in general, two archetypal emission bands at ~430 nm (weak) and ~ 630 nm (strong) with large Stokes shifts (250–275 nm) of ESIPT phenomenon have been observed. The slow shift of emission maxima of the ESIPT fluorescence as a function of decreasing temperature without photoluminescence quenching coupled with the estimated tilt angle (?) of the slices normal to the columnar axis (37 to 42o), from the XRD data, confirm the formation of so-called Scheibe or J-aggregates. The redox activity, metal ion sensing ability, and solvatochromism of the mesogens have also been investigated. The study suggests that these ESIPT Col LCs with band-gap of about 3 eV can be regarded as wide-bandgap semiconducting materials having the electronic characteristics falling between those of conventional semiconductors and insulators.
- Kanakala, Madhu Babu,Yelamaggad, Channabasaveshwar V.
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- Development and structure-activity relationship study of SHP2 inhibitor containing 3,4,6-trihydroxy-5-oxo-5H-benzo[7]annulene
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SHP2, a non-receptor protein tyrosine phosphatase encoded by PTPN11 gene, plays an important role in the cell growth and proliferation. Activating mutations of SHP2 have been reported as a cause of various human diseases such as solid tumors, leukemia, and Noonan syndrome. The discovery of SHP2 inhibitor can be a potent candidate for the treatment of cancers and SHP2 related human diseases. Several reports on a small molecule targeting SHP2 have published, however, there are limitations on the discovery of SHP2 phosphatase inhibitors due to the polar catalytic site environment. Allosteric inhibitor can be an alternative to catalytic site inhibitors. 3,4,6-Trihydroxy-5-oxo-5H-benzo[7]annulene 1 was obtained as an initial hit with a 0.097 μM of IC50 from high-throughput screening (HTS) study. After the structure-activity relationship (SAR) study, compound 1 still showed the most potent activity against SHP2. Moreover, compound 1 exerted good potency against SHP2 expressing 2D and 3D MDA-MB-468.
- Kim, Bohee,Jo, Seungjin,Park, Sung Bum,Chae, Chong Hak,Lee, Kwangho,Koh, Byumseok,Shin, Inji
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supporting information
(2019/11/29)
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- A preparation method of electronic grade gallic octyl ester
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The present invention provides a kind of electronic grade gallic octyl ester of preparation method, which belongs to the technical field of organic synthesis. The gallic acid dissolved in alcohol, then drop adds the chlorination [...], then adding aromatic hydrocarbon solvent, a catalytic amount of B (C6F5) 3 and octanol, moiety will be distillation after the exchange, getting the gallic octyl ester. This method avoids the use of heavy metal catalyst, high yield, low cost, and is suitable for industrial scale production, the ester exchange after the end of the added metal ion adsorbent after the metal ion adsorption, distillation electronic level of gallic octyl ester.
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Paragraph 0023; 0024; 0028; 0029; 0030
(2019/03/31)
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- Self-assembly of taper- and wedge-shaped maleimide derivatives: Synthesis and structure-property relationship
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Herein, we describe design and synthesis of five new amphiphilic systems, viz. 10b-c and 11a-c composed of maleimide at the focal point and alkoxy phenyl ring at the periphery. Their self-assembling behaviour was examined systematically by varying the length of hydrophobic part and aromatic core segment. Evidently, on increasing the aromatic core length, maleimide based amphiphiles relatively emerge as two distinct molecular structures, i.e. wedge- and tapered-shaped. The mesomorphic studies of the two series reveal that, tapered-shaped maleimide derivatives assemble into a smectic A phase with an interesting phasmidic arrangement, whereas the wedge-shaped molecules exclusively form a prospective supramolecular hexagonal columnar mesophase through the intermolecular hydrogen-bonding via maleimide head group. These self-assembled materials could demonstrate high-sensitivity towards various external stimuli.
- Vinayakumara,Kumar, Sandeep,Prasad, S. Krishna,Adhikari, Airody Vasudeva
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p. 765 - 772
(2019/04/25)
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- Synthesis and evaluation of novel benzotropolones as Atg4B inhibiting autophagy blockers
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Autophagy is an intracellular degradation/recycling pathway that provides nutrients and building blocks to cellular metabolism and keeps the cytoplasm clear of obsolete proteins and organelles. During recent years, dysregulated autophagy activity has been reported to be a characteristic of many different disease types, including cancer and neurodegenerative disorders. This has created a strong case for development of autophagy modulating compounds as potential treatments for these diseases. Inhibitors of autophagy have been proposed as a therapeutic intervention in, e.g., advanced cancer, and inhibiting the cysteine protease Atg4B has been put forward as a main strategy to block autophagy. We recently identified and demonstrated -both in vitro and in vivo - that compounds with a benzotropolone basic structure targeting Atg4B, can significantly slow down tumor growth and potentiate the effect of classical chemotherapy. In this study we report the synthesis and inhibition profile of new benzotropolone derivatives with additional structural modifications at 6 different positions. To obtain a solid inhibition profile, all compounds were evaluated on three levels, including two cell-based assays to confirm autophagy and intracellular Atg4B inhibition and an SDS-PAGE-based experiment to assess in vitro Atg4B affinity. Several molecules with a promising profile were identified.
- Tanc, Muhammet,Cleenewerck, Matthias,Kurdi, Ammar,Roelandt, Ria,Declercq, Wim,De Meyer, Guido,Augustyns, Koen,Martinet, Wim,Van der Veken, Pieter
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p. 163 - 168
(2019/03/19)
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- Optoelectronic exploration of novel non-symmetrical star-shaped discotic liquid crystals based on cyanopyridine
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A novel family of non-symmetrical star-shaped cyanopyridine based discotic liquid crystals (CPBz6, CPBz8 and CPBz12) was designed and synthesized, as potential luminescent materials for optoelectronic applications. The length of one of the arms in the design was systematically varied to determine the structure-property relationships. Evidently, all of the compounds exhibited a highly prospective ordered columnar mesomorphism stabilized at ambient temperature with advantageous very low isotropization temperatures. Furthermore, their photophysical characteristics were investigated in depth, both in solution and in the liquid crystal (LC) state. The discotics were found to be intense blue emitters with reasonably good quantum efficiency. Their dynamic intramolecular charge-transfer (ICT) behaviour was confirmed by steady-state absorption and fluorescence spectral analysis in varied solvent polarity. Furthermore, their electrochemical properties were studied from the combination of an experimental method and the theoretical simulations, which elucidated the low laying frontier molecular orbitals (FMOs) with a narrow energy band gap of ～2.0 eV. The resulted visually perceivable emission with favourable energy levels showcases their possible application in electronic display devices.
- Vinayakumara,Swamynathan,Kumar, Sandeep,Adhikari, Airody Vasudeva
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p. 16999 - 17008
(2018/10/24)
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- A sensitive and selective sensor for picric acid detection with a fluorescence switching response
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A low molecular weight organogelator containing 3,5-substituted-1,3,4-oxadiazole and tetrazole units was synthesized and characterized. This compound is only soluble in DMSO and forms a stable gel. The solution and gel exhibit a blue light emission. The gel was characterized by atomic force microscopy, field-emission scanning electron microscopy, 1H NMR and fluorescence measurements. The gel to solution interconversion was reversible for many cycles of heating and cooling. The compound in solution exhibited a high selectivity for the detection of picric acid, a common explosive and water pollutant. Fluorimetric titration studies with nitro explosive compounds revealed that the emission of the compound was red shifted in response to the addition of picric acid, and exhibited a shifting of fluorescence from blue to green. Theoretical and experimental studies revealed that the sensing is due to the complexation of the picrate anion with the protonated fluorophore. The shifting of emission in response to picric acid in the visible region is ideal for the naked eye detection of explosives and therefore it is promising in comparison to the detection methods based on fluorescence quenching.
- Nath, Subrata,Pathak, Suraj Kumar,Pradhan, Balaram,Gupta, Ravindra Kumar,Reddy, K. Anki,Krishnamoorthy,Achalkumar, Ammathnadu S.
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p. 5382 - 5394
(2018/03/30)
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- Synthesis and in vitro antimalarial activity of alkyl esters of gallate as a growth inhibitor of plasmodium falciparum
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This study is aimed to synthesize alkyl esters gallate and determine its in vitro antimalarial activity against parasite Plasmodium falciparum. Fourteen compounds of alkyl esters gallate were synthesized by esterification of the carboxyl group of gallic acid with a series of alkyl alcohols, as well as methoxylation of the hydroxy groups on the aromatic ring of gallic acid. Antimalarial activity of the synthesized alkyl esters gallate were expressed by IC50 value, with gallic acid as an original compound and artemisin as a positive control. Compared to gallic acid, eleven synthesized compounds of alkyl esters gallate, have a greater antimalarial activity against Plasmodium falciparum. On the other hand, three compounds, that are propyl gallate, butyl gallate and trimethoxy methyl gallate, showed a lower antimalarial activity. Moreover, compared to gallic acid (IC50: 194.86 mM) and artemisin (IC50: 0.5 mM), two synthesized compounds of alkyl gallates, namely methyl gallate and hexyl gallate exhibited the stronger antimalarial activity against Plasmodium falciparum, with IC50 value of 0.03 mM and 0.11 mM, respectively. Our result clearly demonstrated that methyl gallate and hexyl gallate as a promising candidate for the new antimalarial agents.
- Arsianti, Ade,Astuty, Hendri,Fadilah,Simadibrata, Daniel Martin,Adyasa, Zoya Marie,Amartya, Daniel,Bahtiar, Anton,Tanimoto, Hiroki,Kakiuchi, Kiyomi
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p. 655 - 662
(2018/05/28)
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- HALOGENATED BENZOTROPOLONES AS ATG4B INHIBITORS
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The present invention relates to compounds having a benzotropolone core, and compositions containing said compounds acting as ATG4B inhibitors, thereby inhibiting autophagy. Moreover, the present invention provides processes for the preparation of the disclosed compounds, as well as methods of using them, for instance as a medicine, in particular for the treatment of cell proliferative disorders, such as cancer.
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Page/Page column 33; 40
(2018/06/12)
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- Rational Design of Supramolecular Dynamic Protein Assemblies by Using a Micelle-Assisted Activity-Based Protein-Labeling Technology
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The self-assembly of proteins into higher-order superstructures is ubiquitous in biological systems. Genetic methods comprising both computational and rational design strategies are emerging as powerful methods for the design of synthetic protein complexes with high accuracy and fidelity. Although useful, most of the reported protein complexes lack a dynamic behavior, which may limit their potential applications. On the contrary, protein engineering by using chemical strategies offers excellent possibilities for the design of protein complexes with stimuli-responsive functions and adaptive behavior. However, designs based on chemical strategies are not accurate and therefore, yield polydisperse samples that are difficult to characterize. Here, we describe simple design principles for the construction of protein complexes through a supramolecular chemical strategy. A micelle-assisted activity-based protein-labeling technology has been developed to synthesize libraries of facially amphiphilic synthetic proteins, which self-assemble to form protein complexes through hydrophobic interaction. The proposed methodology is amenable for the synthesis of protein complex libraries with molecular weights and dimensions comparable to naturally occurring protein cages. The designed protein complexes display a rich structural diversity, oligomeric states, sizes, and surface charges that can be engineered through the macromolecular design. The broad utility of this method is demonstrated by the design of most sophisticated stimuli-responsive systems that can be programmed to assemble/disassemble in a reversible/irreversible fashion by using the pH or light as trigger.
- Sandanaraj, Britto S.,Reddy, Mullapudi Mohan,Bhandari, Pavankumar Janardhan,Kumar, Sugam,Aswal, Vinod K.
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supporting information
p. 16085 - 16096
(2018/10/15)
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- Synthetic method of gallic acid lower alkanol ester
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A synthetic method of gallic acid lower alkanol ester comprises the following steps of: (1) placing gallic acid and lower alkanol in a reactor, adding a sulfonic acid resin catalyst subjected to hydrophobic modification, carrying out stirring, heating to a temperature of 65 to 120 DEG C, performing the reaction for 4 to 10h and filtering to obtain filtrate; (2) removing excessive alcohol in the filtrate by evaporation so as to obtain a crude product, then carrying out recrystallization by deionized water, and carrying out suction filtration and drying to obtain the gallic acid lower alkanol ester. The synthetic method disclosed by the invention is simple, is safe to operate; yield of the gallic acid lower alkanol ester is greater than or equal to 92 percent; product purity is more than or equal to 99.5 percent; moreover, the catalyst has excellent performance; the water distribution link in a conventional method is reduced; a reaction apparatus is simplified; the synthetic method has good repeatability.
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Paragraph 0026
(2017/01/12)
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- s-Triazine-Based Functional Discotic Liquid Crystals: Synthesis, Mesomorphism and Photoluminescence
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A new series of C3-symmetric, π-conjugated molecules was designed, synthesized and characterized. The materials were derived from electron-accepting s-triazine, appended covalently to electron-donating styrylbenzene arms, and were readily prepared in excellent yield with high purity by means of three-fold condensation of triphosphonate with n-alkoxybenzaldehydes under Horner–Wadsworth–Emmons reaction conditions. Examination of the phase transitional properties by several complementary techniques evidenced self-assembly into a hexagonal columnar phase, occurring over wide and reasonable thermal ranges. The photophysical properties were studied both in solution and in the fluid/frozen columnar states by UV/Vis absorption and photoluminescence spectroscopy. The emission spectra obtained as a function of the temperature rule out the breaking-up of larger columns and a non-radiative, thermally activated process. A study carried out on thin films of the glassy columnar state, which accounts for conserved fluorescence, defect-free orientation, and freezing ionic species, with the help of atomic force microscopy (AFM) images, suggested a homogeneous granular morphology comprising fibrillar structures. Dissimilarities in the surface morphology and birefringence of thin films of the solid and frozen columnar states were clearly shown by Raman spectroscopy. An electrochemical investigation revealed a LUMO energy of ?4.0 eV. Thus, the discotic motifs presented herein meet certain criteria of organic materials, which are essential for developing electronic devices.
- Veerabhadraswamy, B. N.,Dambal, Hashambi K.,Rao, D. S. Shankar,Yelamaggad, C. V.
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p. 2225 - 2237
(2016/08/27)
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- COMBINATION OF COMPOUNDS DERIVED FROM GALLIC ACID FOR THE TREATMENT OF CANCER
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The invention relates to a combination of compounds derived from gallic acid, with an antitumoral and antimetastatic activity via a mechanism that involves the induction of apoptosis and the immunogenic death of the tumour cells and the subsequent activation of the specific immune response. The invention also relates to a composition containing a combination of derivatives of gallic acid and pharmaceutically acceptable excipients for the production of useful medicaments in the treatment of cancer. The invention further relates to the use of said composition in a coadjuvant in conventional chemotherapy, reducing the doses of chemptherapeutic agents used in the treatment of cancer.
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- Microwave-assisted esterification of gallic acid
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An efficient synthesis of alkyl gallates under microwave irradiation was described. The reaction took place in 6-10 mins, which was much shorter than the traditional synthetic methods, with almost quantitative yields.
- Shi, Zhi-Hao,Li, Nian-Guang,Tang, Yu-Ping,Shi, Qian-Ping,Zhang, Wei,Zhang, Peng-Xuan,Li, Wei,Dong, Ze-Xi,Duan, Jin-Ao
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p. 1351 - 1354
(2016/06/13)
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- Linear and branched alkyl-esters and amides of gallic acid and other (mono-, di- and tri-) hydroxy benzoyl derivatives as promising anti-HCV inhibitors
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Linear and branched compounds that contain two, three or five units of galloyl (3,4,5-trihydroxybenzoyl) or its isomer 2,3,4-trihydroxybenzoyl, as well as other mono- or dihydroxybenzoyl moieties have been synthesized. These molecules have been evaluated for their in vitro inhibitory effects against a wide panel of viruses showing preferential activity against HIV and HCV. Our structure-activity relationship studies demonstrated that the 2,3,4-trihydroxybenzoyl moiety provides better antiviral activities than the galloyl (3,4,5-trihydroxybenzoyl) moiety that is present in natural green tea catechins. This observation can be of interest for the further rational exploration of compounds with anti-HCV/HIV properties. The most notable finding with respect to HIV is that the tripodal compounds 43 and 45, with three 2,3,4-trihydroxybenzoyl moieties, showed higher activities than linear compounds with only one or two. With respect to HCV, the linear compounds, 52 and 41, containing a 12 polymethylene chain and two 2,3 di- or 2,3,4 tri-hydroxybenzoyl groups respectively at the ends of the molecule showed good antiviral efficiency. Furthermore, the anti-HCV activity of both compounds was observed at concentrations well below the cytotoxicity threshold. A representative member of these compounds, 41, showed that the anti-HCV activity was largely independent of the genetic make-up of the HCV subgenomic replicon and cell lines used.
- Rivero-Buceta, Eva,Carrero, Paula,Doyagüez, Elisa G.,Madrona, Andrés,Quesada, Ernesto,Camarasa, María José,Peréz-Pérez, María Jesús,Leyssen, Pieter,Paeshuyse, Jan,Balzarini, Jan,Neyts, Johan,San-Félix, Ana
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p. 656 - 671
(2015/01/30)
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- Sulfonamide and urea-based anions chemosensors
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The detection of anions has attracted considerable interest because of their importance in various physiological processes. In this study, two sulfonamide and urea-based compounds (1a and 1b) were successfully developed and their spectroscopic and anion recognition properties were fully investigated. These results showed that: (1) compounds showed high selectivity towards cyanide and fluoride ions in CH3CN; (2) compounds only exhibited a large change in fluorescence in the presence of cyanide ions in CH3CN-H2O (95:5, v/v); and (3) compound 1b could act as a gel in dimethyl sulfoxide that transforms into a homogeneous solution upon exposure to cyanide ions. This research suggests that sulfonamide and urea can act as hydrogen-bond donors and provides an alternative approach to the design of novel anion chemosensors.
- Hu, Fang,Cao, Meijiao,Huang, Juanyun,Chen, Zhao,Wu, Di,Xu, Zhiqiang,Liu, Sheng Hua,Yin, Jun
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p. 108 - 115
(2015/04/27)
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- Development of hydrogel lenses with surface-immobilized PEG layers to reduce protein adsorption
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This paper describes the synthesis and characterization of a series of poly(2-hydroxyethyl methacrylate) (pHEMA)-based hydrogel lenses coated with poly(ethylene glycol) (PEG) chains. A novel tri-branched PEG-substituted hydrazide is synthesized, which imparts densely packed, covalently bound PEG layers on hydrogels, to determine whether branching provides improved coverage of the lens surface, thereby reducing protein adsorption. Surface modification of hydrogels with PEG was performed via amide-coupling reactions between PEG-substituted hydrazide and the pHEMA matrix. Protein adsorption, water content, optical transparency, and surface properties of the hydrogels were investigated. The hydrogels exhibited transmittance of >90% and improved surface hydrophilicity. Notably, the amount of lysozyme adsorbed on tri-branched PEGcoated hydrogels decreased significantly compared to the amount adsorbed onto the surface of control and linear PEG-coated hydrogels. These results provide insight into the mechanism by which PEGs reduce lysozyme adsorption and suggest that PEG coating may offer an intriguing potential for ophthalmic biomaterials as well as protein-resistant devices.
- Jee, Jun-Pil,Kim, Ho-Joong
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p. 2682 - 2687
(2015/11/17)
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- Columnar liquid crystalline self-assembly of hydrogen-bonded rod-coil diblock complexes created from pyrazole/benzoic acid derivatives
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We synthesized hydrogen-bonded rod-coil diblock complexes having both a rigid rod and a flexible coil by combining bithiophene-conjugated pyrazole derivatives and alkoxy-substituted benzoic acid derivatives. Their self-assembled nanostructures were investigated using polarized optical microscopy, molecular modeling, and X-ray scattering in liquid crystalline (LC) state. They form different types of supramolecularLCphases depending on the numbers and lengths of alkoxy substituents in the benzoic acids. Diblock complexes with low volume ratios of aliphatic coils to rod segments (dioctyloxy chains) self-assembled into lamellar phases; systems with higher ratios (didodecyloxy, trioctyloxy, and tridodecyloxy chains) formed columns. In these columnar structures, two pyrazoles and two benzoic acids formed an aromatic tetramer core through N-H···O and O-H···N hydrogen bonds. Two sets of aromatic tetramers surrounded by flexible aliphatic chains were then stacked to give columnar phases. These are novel examples of supramolecular LC structures comprising hydrogen-bonded pyrazole-benzoic acid derivatives with tetrameric rigid aromatic scaffolds.
- Kim, Ho-Joong,Cho, Sung,Park, Jung Su
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p. 2740 - 2745
(2015/11/17)
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- ANTAGONISTS OF THE TOLL-LIKE RECEPTOR 1/2 COMPLEX
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Provided are compounds, compositions and methods for treating Toll-like receptor 1/2 complex (TLRI/2) related inflammatory disorders. Small molecules, based on the benzotropolone scaffold, capable of influencing downstream signaling are dislcosed as well as methods of making and modifying these molecules. Also provided are methods for treating a subject for a clinical condition associated with Toll? like receptor complex 1/2 activation, comprising administering to the subject an effective amount of a benzotropolone compound.
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Page/Page column 24
(2014/02/16)
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- Antifungal activity of alkyl gallates against plant pathogenic fungi
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The antifungal activity of alkyl gallates against plant pathogenic fungi was evaluated. All of the fungi tested in this study were susceptible to some alkyl gallates, and the effect of linear alkyl gallates against plant pathogenic fungi was similar to the previously reported effects against Gram-negative and Gram-positive bacteria. We found that branched alkyl gallates showed stronger activity than did linear alkyl gallates with similar log P values. In addition, the antifungal activity of alkyl gallates was correlated with gallate-induced inhibition of the activity of mitochondrial complex II. The antifungal activity of alkyl gallates likely originates, at least in part, from their ability to inhibit the membrane respiratory chain.
- Ito, Shinsaku,Nakagawa, Yasutaka,Yazawa, Satoru,Sasaki, Yasuyuki,Yajima, Shunsuke
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p. 1812 - 1814
(2014/04/17)
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- Self-assembly of hekates-tris(N -salicylideneaniline)s into columnar structures: Synthesis and characterization
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Two series of new, photoluminescent star-shaped discotic liquid crystals, recently termed as "hekates", derived from tris(N-salicylideneaniline) s (TSANs), were synthesized by the facile threefold condensation of 3,4-bis(alkoxy)phenyl 4-aminobenzoates/3,4,5-tris(alkoxy) phenyl 4-aminobenzoates with 1,3,5-triformylphloroglucinol and characterized. These two series of discotics with six and nine peripheral n-alkoxy tails were especially designed and accomplished to understand the relation between mesomorphic/photophysical properties and molecular structure. Proton NMR spectral analysis revealed their existence as an inseparable mixture of two keto-enamine tautomeric forms featuring C3h and Cs rotational symmetries. A systematic study into the thermotropic liquid crystal behavior using polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering confirmed the presence of columnar (Col) phase in vast majority of the TSANs prepared. The two-dimensional (2D) lattices of these fluid columnar phases were found to be characteristic of hexagonal Col (Col h), rectangular Col (Colr), or oblique Col (Col ob) phases depending on the number/length of the peripheral flexible chains. The stabilization of the Colob phase, a less commonly found fluid columnar structure, and the first of its kind in TSAN systems, implies very intensive intermolecular (face-to-face) interactions among the TSAN cores within the column. The photophysical properties were investigated both in solution and the columnar states by UV-vis absorption and photoluminescence; markedly, the solution state emits light in the blue region. The light-emitting ability of the Col phase is particularly significant given the possibility that, in such cores, the protons and electrons interact with each other through the H-bonding environment.
- Achalkumar, Ammathnadu S.,Hiremath, Uma S.,Rao, D. S. Shankar,Prasad, S. Krishna,Yelamaggad, Channabasaveshwar V.
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p. 527 - 544
(2013/03/13)
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- Exploring nature profits: Development of novel and potent lipophilic antioxidants based on galloyl-cinnamic hybrids
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Phenolic acids are ubiquitous antioxidants accounting for approximately one third of the phenolic compounds in our diet. Their importance was supported by epidemiological studies that suggest an inverse relationship between dietary intake of phenolic antioxidants and the occurrence of diseases, such as cancer and neurodegenerative disorders. However, until now, most of natural antioxidants have limited therapeutic success a fact that could be related with their limited distribution throughout the body and with the inherent difficulties to attain the target sites. The development of phenolic antioxidants based on a hybrid concept and structurally based on natural hydroxybenzoic (gallic acid) and hydroxycinnamic (caffeic acid) scaffolds seems to be a suitable solution to surpass the mentioned drawbacks. Galloyl-cinnamic hybrids were synthesized and their antioxidant activity as well as partition coefficients and redox potentials evaluated. The structure-property-activity relationship (SPAR) study revealed the existence of a correlation between the redox potentials and antioxidant activity. The galloyl-cinnamic acid hybrid stands out as the best antioxidant supplementing the effect of a blend of gallic acid plus caffeic acid endorsing the hypothesis that the whole is greater than the sum of the parts. In addition, some hybrid compounds possess an appropriate lipophilicity allowing their application as chain-breaking antioxidant in biomembranes or other type of lipidic systems. Their predicted ADME properties are also in accordance with the general requirements for drug-like compounds. Accordingly, these phenolic hybrids can be seen as potential antioxidants for tackling the oxidative status linked to the neurodegenerative, inflammatory or cancer processes.
- Teixeira, Jose,Silva, Tiago,Benfeito, Sofia,Gaspar, Alexandra,Garrido, E. Manuela,Garrido, Jorge,Borges, Fernanda
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p. 289 - 296
(2013/05/22)
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- Discovery of small-molecule inhibitors of the TLR1/TLR2 complex
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An important regulator of innate immunity, the protein complex of Toll-like receptors 1 and 2 (TLR1/TLR2) provides an attractive target for the treatment of various immune disorders. The novel compound CU-CPT22 can compete with the binding of the specific lipoprotein ligand to TLR1/TLR2 (see picture) with high inhibitory activity and specificity. Repression of downstream signaling from TNF-α and IL-1β was also observed. Copyright
- Cheng, Kui,Wang, Xiaohui,Zhang, Shuting,Yin, Hang
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supporting information
p. 12246 - 12249
(2013/02/23)
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- Alkyl hydroxybenzoic acid derivatives that inhibit HIV-1 protease dimerization
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The therapeutic potential of gallic acid and its derivatives as anti-cancer, antimicrobial and antiviral agents is well known. We have examined the mechanism by which natural gallic acid and newly synthesized gallic acid alkyl esters and related protocatechuic acid alkyl esters inhibit HIV-1 protease to compare the influence of the aromatic ring substitutions on inhibition. We used Zhang-Poorman's kinetic analysis and fluorescent probe binding to demonstrate that several gallic and protecatechuic acid alkyl esters inhibited HIV-1 protease by preventing the dimerization of this obligate homodimeric aspartic protease rather than targeting the active site. The tri-hydroxy substituted benzoic moiety in gallates was more favorable than the di-substituted one in protocatechuates. In both series, the type of inhibition, its mechanism and the inhibitory efficiency dramatically depended on the length of the alkyl chain: no inhibition with alkyl chains less than 8 carbon atoms long. Molecular dynamics simulations corroborated the kinetic data and propose that gallic esters are intercalated between the two N- and C-monomer ends. They complete the β-sheet and disrupt the dimeric enzyme. The best gallic ester (14 carbon atoms, Kid of 320 nM) also inhibited the multi-mutated protease MDR-HM. These results will aid the rational design of future generations of non-peptide inhibitors of HIV-1 protease dimerization that inhibit multi-mutated proteases. Finally, our work suggests the wide use of gallic and protocatechuic alkyl esters to dissociate intermolecular β-sheets involved in protein-protein interactions.
- Flausino Jr., O. A.,Dufau, L.,Reboud-Ravaux, M.,Regasini, L. O.,Petronio, M. S.,Silva, D. H. S.,Bolzani, V. S.,Rose, T.
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p. 4534 - 4540,7
(2012/12/12)
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- Suppression of TNF-α induced NFκB activity by gallic acid and its semi-synthetic esters: Possible role in cancer chemoprevention
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Gallic acid (3,4,5-trihydroxybenzoic acid), found in many plants either in free-form or part of tannins, is known to possess anti-microbial, antioxidant and cytotoxic properties. NFκB regulates the expression of several genes involved in carcinogenesis. These include anti-apoptotic, cytokines and cell cycle-regulatory genes. It is well established that the transcriptional factor NFκB is deregulated in many forms of cancer. Thus, agents that can suppress NFκB activation have the potential of suppressing carcinogenesis. In the present investigation, gallic acid was isolated from Alchornea glandulosa (Euphorbiaceae) and eight esters were synthesised. These compounds were evaluated against TNF-α-induced NFκB activation with stably transfected 293/NFκB-Luc human embryonic kidney cells. Gallates with IC50 values in a range of 10-56 M mediated inhibitory activity higher than gallic acid (IC50 76.0 4.9 M). In addition to inhibiting NFκB activation, gallic acid mediated a modest cytotoxic effect, and some of the gallates affected cell viability at the tested concentrations. Based on these results, suppression of NFκB activation by gallate esters could play a chemopreventive role in carcinogenesis.
- Morais, Mauro C. C.,Luqman, Suaib,Kondratyuk, Tamara P.,Petronio, Maicon S.,Regasini, Luis O.,Silva, Dulce H. S.,Bolzani, Vanderlan S.,Soares, Christiane P.,Pezzuto, John M.
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experimental part
p. 1758 - 1765
(2011/01/12)
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- Columnar liquid-crystalline phase from a series of symmetrical bent diphenylamine derivatives: Synthesis and characterization
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A series of symmetrical bent-shaped materials with six alkoxy chains at the terminal position has been designed and synthesized. All except one exhibit columnar mesophase behavior. The mesomorphic properties of the compounds have been studied with the help of polaralizing optical microscopy (POM) and differential scanning colorimetry (DSC) experiments.
- Majumdar,Ansary, Inul,Roy
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scheme or table
p. 160 - 167
(2011/05/03)
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- Isolation, synthesis, and neurite outgrowth-promoting activity of illicinin A from the flowers of Illicium anisatum
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Two new prenylated C6-C3 compounds, illicinin A (1) and (4S)-illicinone I (2), were isolated from the flowers of Illicium anisatum. The structures of the new compounds were elucidated by spectroscopic methods. The absolute structure of (4S)-illicinone I was determined by comparing its CD spectrum and specific rotation with those of (4S)-illicinone A (4). Illicinin A (1) and 4-allyl-2,6-dimethoxy-3-(3-methylbut-2-enyl)phenol (3) were found to exhibit neurite outgrowth-promoting activity at concentrations ranging from 0.1 to 10 μM in primary cultured rat cortical neurons. Illicinin A and its derivatives were synthesized for structure-activity relationship studies by employing sequential Stille reactions to introduce a prenyl and an allyl group to the benzene ring, thereby indicating that an allylphenyl moiety in the molecule of 1 is essential for its neurotrophic properties.
- Takaoka, Shigeki,Takaoka, Noriko,Minoshima, Yuka,Huang, Jian-Mei,Kubo, Miwa,Harada, Kenichi,Hioki, Hideaki,Fukuyama, Yoshiyasu
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experimental part
p. 8354 - 8361
(2009/12/26)
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- A new disc-shaped mesogenic compound with olefinic linkage derived from triphenylamine: synthesis, mesogenic behavior and fluorescence properties
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A new disc-like triphenylamine containing mesogenic compound has been synthesized by the implementation of the Heck and ring-closing metathesis-based reactions in good yield. The designed and synthesized compound showed rectangular columnar mesophase and this is the first report of liquid crystalline phase of the triphenylamine-based compound with an olefinic linkage. The disc-shaped compound exhibited excellent fluorescence properties.
- Majumdar, Krishna C.,Chattopadhyay, Buddhadeb,Shyam, Pranab Kumar,Pal, Nilasish
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scheme or table
p. 6901 - 6905
(2010/04/30)
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- Chemoselective esterification of phenolic acids in the presence of sodium bicarbonate in ionic liquids
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Chemoselective esterification of phenolic acids with dialkyl sulphates or alkyl halides in the presence of sodium bicarbonate in 1,3-dialkylimidazolium ionic liquids is reported in excellent yields and less reaction time as compared to organic solvents. Copyright Taylor & Francis Group, LLC.
- Ambika,Singh, Pradeep Pratap,Chauhan
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p. 928 - 936
(2008/09/17)
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- Antiproliferative and apoptosis-inducing activities of alkyl gallate and gallamide derivatives related to (-)-epigallocatechin gallate
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Green tea and (-)-epigallocatechin gallate (EGCG: one of the main components of green tea) are reported to have cancer-preventive activity in humans. A previous SAR study of EGCG and derivatives indicated that a galloyl group is essential for the activity. To test this hypothesis, we synthesized various alkyl gallate and gallamide derivatives and evaluated their antiproliferative effects on human leukemia HL-60 cells. Dodecyl 3,4,5-trihydroxybenzoate (6c) showed the most potent activity, being more potent than EGCG. To clarify the molecular mechanism of the antiproliferative action, we investigated the effects of 6c on various factors. Compound 6c was found to induce apoptosis mediated by endoplasmic reticulum (ER)-stress-related caspase-12. Upregulation of gadd-153, an ER-stress marker protein, was also observed. These results indicate that 6c induced apoptosis via the ER-stress-related pathway.
- Dodo, Kosuke,Minato, Taro,Noguchi-Yachide, Tomomi,Suganuma, Masami,Hashimoto, Yuichi
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p. 7975 - 7982
(2008/12/23)
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- Evaluation of anti-herpetic and antioxidant activities, and cytotoxic and genotoxic effects of synthetic alkyl-esters of gallic acid
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The n-alkyl esters of gallic acid (CAS 138-57-8) have a diverse range of uses as anti-oxidants in food, cosmetics and pharmaceutical industries. Pharmaceutical studies performed with these compounds have found that they have many therapeutic potentialities including anti-cancer, antiviral and antimicrobial properties. However, more interest has been devoted to their antioxidant activity due to the ability to scavenge and reduce reactive oxygen species (ROS) formation. In this study, gallic acid and 14 different alkyl gallates were tested. The cytotoxicity and anti-herpetic (HSV-1, KOS and 29-R strains) activity were studied by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) colorimetric assay and the cell viability by using the Trypan blue dye exclusion method. The genotoxicity was studied by the Comet assay and the antioxidant activity by using the DPPH (1,1-diphenyl-2- picrylhydrazyl) radical scavenging and microsomal lipid peroxidation-inhibiting activities. The results showed that all the tested compounds have anti-herpetic activity at non cytotoxic concentrations with selectivity indices (SI = CC 50/EC50) varying from 0.89 to 18.34, depending on the used HSV-1 strain. It was observed that all tested alkyl gallates showed some degree of genotoxicity, at the tested concentrations, except cetyl gallate, at 256.60 μmol/L (p 50 values varying from 17 to 31 μmol/L; and microsomal lipid peroxidation-inhibiting activity with IC50 values varying from 21 to 59 μmol/L. It was observed that the presence of hydroxyl groups in these molecules is important for their pharmacological profile, but the length of the lateral carbonic chain does not have considerable influence.
- Savi, Luciane A.,Leal, Paulo C.,Vieira, Tiago O.,Rosso, Rober,Nunes, Ricardo J.,Yunes, Rosendo A.,Creczynski-Pasa, Tania B.,Barardi, Celia R. M.,Simoes, Claudia Maria Oliveira
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- SEPARATORY AGENT FOR OPTICAL ISOMER
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The invention provides a separating agent for enantiomeric isomers which has the characteristic ability to identify asymmetry. The separating agent includes as an effective component an aromatic polysaccharide derivative having a C10 or higher alkoxy group as a substituent on the aromatic group.
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- Supramolecular assembly of fluorescent phasmidic diacetylene and its photopolymerization
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The closed micellar triclinic structure of a fluorescent phasmidic diacetylene (PhDO) has been fixed by topochemical photopolymerization which induced fluorescence quenching to offer a novel method of image photopatterning.
- Kim, Bong Gi,Kim, Sehoon,Seo, Jangwon,Oh, Nam-Keun,Zin, Wang-Cheol,Park, Soo Young
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p. 2306 - 2307
(2007/10/03)
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- Potentiation of vasoconstrictor response and inhibition of endothelium-dependent vasorelaxation by gallic acid in rat aorta
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In the isolated rat thoracic aorta, gallic acid potentiated the vasoconstrictor response to phenylephrine. The potentiation produced by gallic acid was absent in endothelium-denuded arteries. The potentiation was abolished by NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthesis, and slightly attenuated by an addition of L-arginine, while indomethacin or BQ610 had no effect. The potentiation of response to phenylephrine was not found for structural modifications of gallic acid, except for caffeic acid. Gallic acid also inhibited vasorelaxation induced by acetylcholine, sodium nitroprusside or prostacyclin, especially that by acetylcholine. The effect on vasorelaxation induced by acetylcholine was decreased by esterification of the carboxy group of gallic acid, and in the absence or by the methylation of the o-dihydroxy group. Caffeic acid inhibited the vasorelaxation, though the effect was smaller than that of gallic acid. These findings indicate that gallic acid produces a potentiation of contractile response and inhibition of vasorelaxant responses, probably through inactivation of nitric oxide (NO), in which endothelially produced NO is principally involved, and that the modification of functional groups of the gallic acid molecule abolishes the potentiation of contractile response and attenuates the inhibition of vasorelaxant responses.
- Sanae, Fujiko,Miyaichi, Yukinori,Hayashi, Hisao
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p. 690 - 693
(2007/10/03)
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- Acetyl bromide-alcohols as convenient reaction systems for: a) Removal of N-tert-Boc, N-Cbz and N-Ac protective groups, b) Esterifications and transesterifications, c) Debenzylation of aryl-O-benzyl ethers
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Hydrogen bromide generated in situ by the addition of acetyl bromide to alcohols is a useful reagent for esterifications and transesterifications; N- tert-Boc, N-Cbz, and N-Ac deprotections; and debenzylation reactions.
- Lesk,Nudelman
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p. 1405 - 1408
(2007/10/03)
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- Novel chemoselective de-esterification of esters of polyacetoxy aromatic acids by lipases
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Candida cylindracea lipase (CCL) and porcine pancreatic lipase (PPL) have been used for deacetylation of peracetates of methyl and ethyl esters of six different polyphenolic acids in organic solvents. Exclusive de-esterification of the ester groups derived from the phenolic hydroxy and aliphatic acid over the ester group of the aromatic acid and aliphatic alcohol has been achieved affording the corresponding esters of phenolic acids in as high yields as 90-97%. The results have been corroborated with the mechanism of lipase action.
- Parmar, Virinder S.,Kumar, Ajay,Bicht, Kirpal S.,Mukherjee, Shubhasish,Prasad, Ashok K.,Sharma, Sunil K.,Wengel, Jesper,Olsen, Carl E.
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p. 2163 - 2176
(2007/10/03)
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- One-Electron Redox Potentials of Phenols. Hydroxy- and Aminophenols and Related Compounds of Biological Interest
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The rate constants for reversible electron transfer between a series of substituted phenolate ions and anilines and various substituted phenoxyl or anilino radicals in aqueous solution were measured by observing the formation or depletion of the radicals involved.Nonequilibrium concentrations of the radicals were produced in the presence of the corresponding phenols or anilines by using the pulse radiolysis technique.The relaxation of the system to equilibrium was monitored by optical detection methods.From the equilibrium constants for one-electron transfer, the one-electron redox potentials (E2) for 38 phenolic or anilino type compounds were determined, many of which are natural products.The redox potentials are strongly influenced by electron-donating or -withdrawing substituents at the aromatic system.
- Steenken, S.,Neta, P.
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p. 3661 - 3667
(2007/10/02)
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