831-61-8Relevant articles and documents
Facile synthesis of new quinoxalines from ethyl gallate by green chemistry protocol
Lima, Rafaely N.,Porto, André L.M.
, p. 825 - 828 (2017)
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.
The effect of solvent composition on grafting gallic acid onto chitosan via carbodiimide
Guo, Ping,Anderson, John D.,Bozell, Joseph J.,Zivanovic, Svetlana
, p. 171 - 180 (2016)
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.
Two asymmetrical perylene diimide derivatives: Synthesis, optical-electrochemical properties and morphologies of self-assembly
Liu, Jian,Song, Yuting,Tao, Jiayu,Xu, Hai-Jun,Zhang, Jiuxuan
, (2021/11/01)
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.
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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Paragraph 0099-0105; 0107, (2021/07/07)
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.
Design, Synthesis, and Antifungal Activity of Alkyl Gallates Against Plant Pathogenic Fungi In Vitro and In Vivo
Zhao, Xiao-Long,Li, Chun-Qing,Song, Xiao-Mei,Yan, Shuang-Mei,Luo, Du-Qiang
, p. 38 - 43 (2021/02/01)
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.
Polyhydroxybenzoic acid derivatives as potential new antimalarial agents
Degotte, Gilles,Francotte, Pierre,Pirotte, Bernard,Frédérich, Michel
, (2021/08/07)
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).
Influence of functional groups on the self-assembly of liquid crystals
Tan, Shanchao,Tao, Jiayu,Luo, Wendi,Jiang, Hao,Liu, Yuhong,Xu, Haijun,Zeng, Qingdao,Shi, Hongyu
supporting information, p. 1149 - 1152 (2020/10/12)
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.
Exceptional dual fluorescent, excited-state intramolecular proton-transfer (ESIPT) columnar liquid crystals characterized by J-stacking and large Stokes shifts
Kanakala, Madhu Babu,Yelamaggad, Channabasaveshwar V.
, (2021/03/19)
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.
Development and structure-activity relationship study of SHP2 inhibitor containing 3,4,6-trihydroxy-5-oxo-5H-benzo[7]annulene
Kim, Bohee,Jo, Seungjin,Park, Sung Bum,Chae, Chong Hak,Lee, Kwangho,Koh, Byumseok,Shin, Inji
supporting information, (2019/11/29)
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.
A preparation method of electronic grade gallic octyl ester
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Paragraph 0023; 0024; 0028; 0029; 0030, (2019/03/31)
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.
