2150-38-1Relevant articles and documents
Kopsirachin, ein ungewoehnliches Alkaloid aus der Apocynaceae Kopsia dasyrachis Ridl.
Homberger, Katharina,Hesse, Manfred
, p. 237 - 248 (1984)
From the leaves of Kopsia dasyrachis Ridl, a new typ of alkaloid, kopsirachine (1) built up from catechin (2) and skytanthine (3) has been isoled.The structure elucidation is based on spectral and chemical evidence.Oxidative cleavage of its derivative 4 with KMnO4 afforded veratric acid which was identified as its methylester by comparison with an authentic sample.Pyrolysis of 1 yielded δ-skythanthine (3).The stereochemistry of the skythanthine substrituents in 1 could not yet be estabilished.
Tyrosinase Inhibitor from Black Rice Bran
Miyazawa, Mitsuo,Oshima, Teruo,Koshio, Katsuya,Itsuzaki, Yumi,Anzai, Jun
, p. 6953 - 6956 (2003)
The inhibitor of tyrosinase activity in black rice bran was investigated. The methanol extract from black rice bran was re-extracted with hexane, chloroform, ethyl acetate, or water. The ethyl acetate extract had the most potent inhibition against tyrosinase activity by 80.5% at a concentration of 0. 4 mg/mL. Inhibitory compound in the ethyl acetate fraction was isolated by silica gel column chromatography, and identified as protocatechuic acid methyl ester (compound 1) by GC, GC-MS, IR, and 1H and 13C NMR spectroscopy. Compound 1 inhibited 75.4% of tyrosinase activity at a concentration of 0.50 μmol/mL. ID50 (50% inhibition dose) value of compound 1 was 0.28 μmol/mL. To study the structure-activity relationship, protocatechuic acid (2), vanillic acid (3), vanillic acid methyl ester (4), isovanillic acid (5), isovanillic acid methyl ester (6), veratric acid (7), and veratric acid methyl ester (8) were also assayed.
Mechanistic studies of base-catalysed lignin depolymerisation in dimethyl carbonate
Dabral, Saumya,Engel, Julien,Mottweiler, Jakob,Spoehrle, Stephanie S. M.,Lahive, Ciaran W.,Bolm, Carsten
, p. 170 - 182 (2018)
The depleting fossil reservoirs have stimulated global research initiatives on renewable lignin feedstocks as sustainable alternatives to petroleum-derived aromatics. Base-catalysed depolymerisation (BCD) is regarded as an economical and efficient approach for the valorisation of technical lignins. The major limiting factor encountered during this process is the re-condensation of the formed phenolic products, which results in lower monomer yields. To diminish these side reactions, we selected alkali earth metal catalysts in dimethyl carbonate (DMC) to produce methylated phenol derivatives as the final products. Herein, we demonstrate for the first time a base-promoted depolymerisation process affording low-molecular weight oils in high yields (52-67 wt%) wherein the employed bases are used in truly catalytic quantities (with catalyst loadings of around 5 mol%). The general applicability of this methodology was proved on four different lignin samples (1 Kraft, 3 organosolv) using caesium carbonate and lithium tert-butoxide as catalysts. The 2D NMR studies on the post-reaction lignin samples showed a similar degradation of the major lignin linkages for both bases. A difference in the reduction of phenolic moieties was revealed by quantitative 31P NMR analysis. Furthermore, GPC analysis demonstrated a significant shift towards lower mass fragments for the Cs2CO3-catalysed lignin degradation. A detailed GC-MS analysis for these samples identified a range of methoxy capped-monomeric degradation products. The scope of this reaction system was further expanded to lignocellulosic biomass such as milled beechwood chips, which notably showed similar product distributions. Based on the correlation of the experimental observations for extracted lignin samples and model compound studies, a mechanistic pathway for the Cs2CO3-catalysed system was suggested. DFT calculations provided reaction pathways for the observed cleavage products.
Novel arylcarbamate-N-acylhydrazones derivatives as promising BuChE inhibitors: Design, synthesis, molecular modeling and biological evaluation
Yamazaki, Diego A.S.,Rozada, Andrew M.F.,Baréa, Paula,Reis, Elaine C.,Basso, Ernani A.,Sarragiotto, Maria Helena,Seixas, Flávio A.V.,Gauze, Gisele F.
, (2021/01/18)
A novel series of arylcarbamate-N-acylhydrazones derivatives have been designed and synthesized as potential anti-cholinesterase agents. In vitro studies revealed that these compounds demonstrated selective for butyrylcholinesterase (BuChE) with potent inhibitory activity. The compounds 10a-d, 12b and 12d were the most potent BuChE inhibitors with IC50 values of 0.07–2.07 μM, highlighting the compound 10c (IC50 = 0.07 μM) which showed inhibitory activity 50 times greater than the reference drug donepezil (IC50 = 3.54 μM). The activity data indicates that the position of the carbamate group in the aromatic ring has a greater influence on the inhibitory activity of the derivatives. The enzyme kinetics studies indicate that the compound 10c has a non-competitive inhibition against BuChE with Ki value of 0.097 mM. Molecular modeling studies corroborated the in vitro inhibitory mode of interaction and show that compound 10c is stabilized into hBuChE by strong hydrogen bond interaction with Tyr128, π-π stacking interaction with Trp82 and CH?O interactions with His438, Gly121 and Glu197. Based on these data, compound 10c was identified as low-cost promising candidate for a drug prototype for AD treatment.
Br?nsted acid-catalyzed chlorination of aromatic carboxylic acids
Yu, Zhiqun,Yao, Hongmiao,Xu, Qilin,Liu, Jiming,Le, Xingmao,Ren, Minna
supporting information, p. 685 - 689 (2021/04/09)
The chlorination of aromatic carboxylic acids with SOCl2 has been effectively performed by reacting with a Br?nsted acid as the catalyst. Based on this discovery, an efficient catalytic method that is cheaper than traditional catalytic methods was developed. 20 substrates were chlorinated offering excellent yields in a short reaction time. And the SOCl2/Br?nsted acid system has been used in a larger scale preparative reaction. A dual activation mechanism was proposed to prove the irreplaceable system of SOCl2/Br?nsted acid.
BCL-2 INHIBITOR
-
Paragraph 0836-0838, (2021/10/22)
Disclosed herein is a compound of Formula (I) for inhibiting both Bcl-2 wild type and mutated Bcl-2, in particular, Bcl-2 G101V and D103Y, and a method of using the compound disclosed herein for treating dysregulated apoptotic diseases.
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).
A multicentre synergistic polyoxometalate-based metal-organic framework for one-step selective oxidative cleavage of β-: O -4 lignin model compounds
Tian, Hong-Rui,Liu, Yi-Wei,Zhang, Zhong,Liu, Shu-Mei,Dang, Tian-Yi,Li, Xiao-Hui,Sun, Xiu-Wei,Lu, Ying,Liu, Shu-Xia
, p. 248 - 255 (2020/01/13)
A novel mixed-valence polyoxovanadate-based copper-organic framework, [CuI(bbi)]2{[CuI(bbi)]2VIV2VV8O26}·2H2O (NENU-MV-5, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)), was facilely synthesized from routine reagents under mild hydrothermal conditions. Using NENU-MV-5 as a heterogeneous catalyst without any co-catalyst, one-step oxidative cleavage of β-O-4 lignin into phenols and aromatic acids with high catalytic activity and selectivity was realized under an oxygen atmosphere. No obvious decrease in activity was observed after five cycles, which indicates the excellent stability and sustainability of NENU-MV-5. The perfect catalytic performance of NENU-MV-5 can be attributed to the multi-site synergistic effect of the mixed-valence VV-O-VIV sites on polyoxovanadate for the oxidation of β-O-4 alcohol to β-O-4 ketone and the Cu(i) sites on the framework for the rapid cleavage of the Cα-Cβ bond of β-O-4 ketone. This system represented the first co-catalyst-free example for the one-step selective degradation of lignin catalyzed by a well-defined crystalline catalyst with definite composition and structure in a single solvent.
Catalytic Activation of Carbon-Hydrogen Bonds in Lignin Linkages over Strong-Base-Modified Covalent Triazine Frameworks for Lignin Oxidative Cleavage
Gao, Jin,Liu, Meng,Shi, Song,Xu, Jie,Zhao, Li,Zhu, Guozhi
, p. 7526 - 7534 (2020/08/21)
The design of highly efficient catalysts for the cleavage of various lignin linkages is the key step in the depolymerization of lignin. In this paper, strong-base-modified covalent triazine frameworks (CTFs) were reported to be effective in the cleavage o
Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
, p. 17887 - 17896 (2020/08/19)
An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
