- Molecular modeling studies and: In vitro screening of dihydrorugosaflavonoid and its derivatives against Mycobacterium tuberculosis
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Novel drug regimens against tuberculosis (TB) are urgently needed and may be developed by targeting essential enzymes of Mtb that sustain the pathogenicity of tuberculosis. In the present investigation, series of compounds (5a-f and 6a-f) based on a naturally occurring rugosaflavonoid moiety were evaluated by in silico molecular modeling studies against β-ketoacyl-ACP reductase (MabA) (PDB ID: IUZN) and pantothenate kinase (PanK) (PDB ID: 3AF3). Compounds 5a, 5c, 5d, and 6c, which had docking scores of -8.29, -8.36, -8.17 and -7.39 kcal mol-1, respectively, displayed interactions with MabA that were better than those of isoniazid (-6.81 kcal mol-1). Similarly, compounds 5a, 5c, 5d, and 6c, which had docking scores of -7.55, -7.64, -7.40 and -6.7 kcal mol-1, respectively, displayed interactions with PanK that were comparable to those of isoniazid (-7.64 kcal mol-1). Because of their docking scores, these compounds were screened in vitro against Mycobacterium tuberculosis H37Ra (Mtb) using an XRMA protocol. Among the screened compounds, the dihydrorugosaflavonoid derivatives 5a, 5c, and 5d had IC50 values of 12.93, 8.43 and 11.3 μg mL-1, respectively, and exhibited better inhibitory activity than the parent rugosaflavonoid derivatives. The rugosaflavonoid derivative 6c had an IC50 value of 17.57 μg mL-1. The synthesized compounds also displayed inhibitory activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. The present study will be helpful for the further development of these molecules into antitubercular lead candidates.
- Puranik, Ninad V.,Srivastava, Pratibha,Swami, Sagar,Choudhari, Amit,Sarkar, Dhiman
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Read Online
- Synthesis of cannabinol by a modified Ullmann-ziegler cross-coupling
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Cannabinol, a pharmaceutically interesting component of cannabis, was prepared by a modified Ullmann-Ziegler cross-coupling. Using easily obtainable starting materials, this convergent approach allows facile access to a variety of cannabinol derivatives. Georg Thieme Verlag Stuttgart New York.
- Nüllen, Max P.,G?ttlich, Richard
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Read Online
- Synthesis of [6,6,m]-Tricyclic Compounds via [4+2] Cycloaddition with Au or Cu Catalyst
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We synthesized [6,6,6]- and [6,6,7]-tricyclic compounds via intramolecular [4+2] cycloaddition by gold or copper catalysts. Substrates for cyclization were prepared by coupling reactions between eight types of diyne and four types of aromatic moieties. We have successfully synthesized eleven tricyclic compounds.
- Kang, Juyeon,Ham, Seunghwan,Seong, Chaehyeon,Oh, Chang Ho
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supporting information
p. 1039 - 1043
(2021/05/05)
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- Investigations on the Photochemical Reaction Mechanisms of Selected Dibenzoylmethane Compounds
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In this work, combined time-resolved spectroscopies of femtosecond transient absorption, nanosecond transient absorption, and DFT calculations were performed to unravel the photocyclization reaction mechanisms of selected dibenzoylmethane (DBM) derivatives, including 2-chloro-1,3-diphenylpropan-1,3-dione (1a), 2-chloro-1-(3,5-dimethoxyphenyl)-3-phenylpropan-1,3-dione (1b), 2-chloro-2-fluoro-1,3-diphenylpropan-1,3-dione (1c), and 2-chloro-2-fluoro-1,3-di(4-methoxyphenyl)propan-1,3-dione (1d). Photocyclization reaction mechanisms for 1a and 1b are similar, where a C-Cl heterolysis occurs yielding an α-ketocation intermediate, followed by cyclization to generate the cation species. On the other hand, 1c and 1d undergo dechlorination primarily producing a radical species, which further experiences cyclization yielding cyclized radical species. The dominant factor leading to the different reaction mechanisms is the involvement of a fluorine atom bonded at α-C. Due to the meta-effect, the p-methoxy substitution on the benzene ring inhibits the photocyclization reaction and reduces the yield of photocyclization.
- Wang, Junxiao,Guo, Yan,Wang, Jialin,Ma, Jiani
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supporting information
p. 7594 - 7602
(2021/06/21)
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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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- ANTIVIRAL COMPOUNDS AND THEIR USE
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The invention relates to compounds that have antiviral activity, particularly 4-oxochromane derivatives that have antiviral activity against viruses of the Family Flaviviridae. Methods of treating viruses with the 4-oxochromane compounds, particularly viruses of the Family Flaviviridae, are also described.
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Paragraph 0081
(2021/04/10)
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- Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
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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.
- Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
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p. 17887 - 17896
(2020/08/19)
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- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
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Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
- Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
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p. 4475 - 4481
(2020/04/10)
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- Nickel-Catalyzed Esterification of Amides Under Mild Conditions
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Abstract: The use of ligands to adjust the catalytic activity of the catalyst for esterification of amides is challenge in organic chemistry. In this paper, Nickel(II)-NHC-catalyzed the esterification reaction between N,N-di-Boc amide and alcohols at room temperature have been demonstrated. The imidazolium salt bearing a hydroxyl functionalized side arm showed high effective catalytic activity in the activation of the amide N–C bond in air atmosphere. Graphic Abstract: [Figure not available: see fulltext.].
- Li, Jun-Fei,Wang, Yao-Fang,Wu, Yuan-Yuan,Liu, Wen-Jing,Wang, Jun-Wen
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p. 874 - 880
(2019/11/13)
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- Synthesis of Some Aromatic and Aliphatic Esters Using WO3/ZrO2 Solid Acid Catalyst under Solvent Free Conditions
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A simple method is delineated for the synthesis of substituted ester products in superior yields by esterification reaction under solvent unbound condition using tungsten upgraded ZrO2 solid acid catalyst at 353 K. The WO3/ZrO2 catalyst has been prepared by using impregnation method followed by calcination at 923 K over a period of 6 h in air atmosphere. SEM, XRD, FTIR, and BET surface area techniques were used to categorize this catalyst. Zirconia has both acidic and basic possessions which can be changed by incorporating suitable promoter atom like tungsten which in turn increases the surface area thereby enhancing the surface acidity. Impregnation of W6+ ions exhibits a strong influence on phase modification of zirconia from thermodynamically solid monoclinic to metastable tetragonal phase. Amalgamation of promoter W6+ will stabilize tetragonal phase which is active in catalyzing reactions. In esterification reaction WO3/ZrO2 catalyst was found to be stable, efficient and environmental friendly, effortlessly recovered by filtration, excellent yield of product and can be reusable efficiently.
- Guguloth, Vijaya Charan,Battu, Satyanarayana
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p. 2153 - 2157
(2020/09/16)
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- Aminopyrimidine compound
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The invention discloses an aminopyrimidine compound. The structural general formula of the compounds is shown as a formula I in the specification. In the formula I, R1 is one of alkyl with a carbon atom total number of 1-6, cycloalkyl with a carbon atom total number of 3-6, halogen substituted alkyl with a carbon atom total number of 1-6 and halogen substituted cycloalkyl with a carbon atom totalnumber of 3-6, R2 is alkoxy with a carbon atom total number of 1-6, halogen substituted alkoxy with a carbon atom total number of 1-6, cycloalkyl with a carbon atom total number of 3-6 and halogen substituted cycloalkyl with a carbon atom total number of 3-6, and X is F, Br or Cl. The compound has a remarkable antibacterial effect and a good drug forming property.
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Paragraph 0091; 0093; 0094 ;0095
(2019/08/12)
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- Hydrazide compounds
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The invention discloses hydrazide compounds. The compounds are characterized by having a structure represented by a formula I shown in the description, wherein Ar1 and Ar2 are each independently selected from the group consisting of aryl, azinyl, piperazinyl, pyrazolyl, imidazolyl, pyrrolyl, phenyl, naphthyl, thiazolyl, thienyl, furyl, aryl, phenyl, piperazinyl, piperidinyl, piperazinyl, and-C13H9represented by a formula 9 shown in the description, only one of the Ar1 and the Ar2 is phenyl, the Ar1 has m substituents R1, Ar2 has n substituents R2, m=0 to 3, and n=0 to 3; and if the formula Ihas a plurality of substituents R1 and R2, the plurality of substituents R1 and R2 are independent with one another, can select the same substituents or different substituents, and the R1 and the R2 are each independently selected from the group consisting of halogen, hydroxyl, cyano, C1-C3 alkyl, C1-C3 alkoxy, amino, C1-C3 alkyl substituted amino, C1-C3 alkyl disubstituted amino, perfluoro C1-C3alkyl and fluoro substituted C1-C3 alkoxy.
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Paragraph 0088; 0095; 0097; 0098
(2019/10/01)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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supporting information
p. 3931 - 3943
(2018/09/11)
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- Composition FOR PREVENTING ALOPECIA AND ACTIVATING HAIR GROWTH
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The present invention provides a hair growth promoter comprising as an active ingredient, a compound having a chemical structure of general formula (1) or a pharmacologically acceptable salt thereof. In the general formula (1): R_1 is a saturated or unsaturated straight chain or branched C1-C10 alkyl group or hydroxy alkyl group; R_2 is hydrogen or a saturated or unsaturated straight chain or branched C1-C10 alkoxy or hydroxy alkoxy; X is hydrogen, hydroxy, or a saturated or unsaturated straight chain or branched C1-C10 alkyl group, alkoxy or hydroxyl alkoxy; R_3 and R_4 are each independently selected from R_5, hydrogen, aldehyde, and a saturated or unsaturated straight chain or branched alkyl, alkoxy, or hydroxy alkoxy; R_5 has a structure of # AAA #; R_6 is selected from hydrogen, and a saturated or unsaturated straight chain or branched C1-C10 alkyl, alkoxy, or hydroxy alkoxy; and one of R_3 and R_4 is hydrogen.COPYRIGHT KIPO 2017
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Paragraph 0194; 0195
(2018/02/16)
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- Cancerous Cell Growth Inhibiting Compounds
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The present invention provides a compound of Formula I, II or III or a salt or prodrug or derivative thereof that is useful for skin-whitening by inhibiting melanin formation and removing existing melanin and the inhibition of melanoma growth and/or the removal of existing melanoma cells.
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Paragraph 0177
(2018/01/03)
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- First synthesis of rugosaflavonoid and its derivatives and their activity against breast cancer
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Rugosaflavonoid, is a secondary metabolite isolated from the plant Rosa rugosa was synthesized in five simple steps from commercially available 3,5-dihydroxy benzoic acid involving domino aldol-Michael-oxidation reaction. This is the first report of the synthesis of rugosaflavonoid (6a). A series of its derivatives were also synthesized, characterized and evaluated for the cytotoxicity against the breast cancer MCF-7 and normal NIH3T3 cell lines. The synthetic derivatives of rugosaflavonoid showed comparable activity in both the cell lines and compounds 6d, 6e and 6f, which were found to be cytotoxic towards MCF-7 cell lines but nontoxic to NIH3T3 cell lines at 5 μM concentration. In an attempt to explore the mode of action of the best active compounds, docking on the ATP binding site of EGFR (1M17) was performed considering that EGFR over-expressed in most of the tumors. The docking score (Gscore) of 6f and standard quercetin was found to be -8.608 and -8.310 respectively.
- Puranik, Ninad V.,Srivastava, Pratibha
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p. 33052 - 33060
(2017/07/07)
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- Development and Application of a Recyclable High-Load Magnetic Co/C Hybrid ROMP-Derived Benzenesulfonyl Chloride Reagent and Utility of Corresponding Analogues
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The development and application of high-load, recyclable magnetic Co/C hybrid ROMP-derived benzenesulfonyl chloride and analogues is reported. The regeneration and utility of these reagents in the methylation/alkylation of various carboxylic acids is demonstrated via efficient retrieval of the magnetic reagent with a neodymium magnet. Additional reactions employing the analogue sulfonic acid and in situ generated magnetic benzenesulfonyl azide are also reported.
- Faisal, Saqib,Zang, Qin,Maity, Pradip K.,Brandhofer, Agnes,Kearney, Patrick C.,Reiser, Oliver,Grass, Robert N.,Stoianova, Diana,Hanson, Paul R.
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supporting information
p. 2274 - 2277
(2017/05/12)
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- Efficient and selective palladium-catalyzed direct oxidative esterification of benzylic alcohols under aerobic conditions
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A highly efficient palladium-catalyzed approach for the direct oxidative esterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions. A variety of esters are obtained in yields of 43–96%.
- Hu, Yongke,Li, Bindong
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p. 7301 - 7307
(2017/11/29)
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- Synthesis of trans-resveratrol using modified Julia olefination route
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Bioactive hydroxystilbinoid-trans-resveratrol [(E)-3,5,4′ trihydroxy stilbene, 1] has been synthesized by modified Julia olefination method. The reaction between corresponding carbanion of benzothiazol-2-yl sulfone derivative and p-anisaldehyde dimethyl acetal with sodium hydride as a base, affords mainly cis-3,5,4′ trimethoxystilbene 10b with minor quantity of trans-isomev. Both the isomers have been separated in pure form and confirmed by their NMR spectral data. Demethylation of cis-3,5,4′ trimethoxystilbene either with AlCVpyridine or AlCl3/triethylamine results in the formation of trans-resveratrol.
- Shenvi, Suvarna,Shivanna, Shivaprakash,Reddy, G. Chandrasekara
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p. 1035 - 1038
(2017/11/10)
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- Synthesis and SAR of 4-methyl-5-pentylbenzene-1,3-diol (MPBD), produced by Dictyostelium discoideum
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4-Methyl-5-pentylbenzene-1,3-diol (MPBD) is a secondary metabolite of SteelyA polyketide synthase, which controls cell aggregation and spore maturation of Dictyostelium discoideum. In this study, chemical synthesis of MPBD and its derivatives was achieved. Structure-activity relationship (SAR) studies for antimicrobial activities against Escherichia coli and Bacillus subtilis were also conducted.
- Murata, Chihiro,Ogura, Tetsuhiro,Narita, Shuhei,Kondo, Anna P.,Iwasaki, Natsumi,Saito, Tamao,Usuki, Toyonobu
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p. 1428 - 1433
(2016/02/19)
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- Cyano-containing resveratrol analogue and preparation method and purpose thereof
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The invention provides a cyano-containing resveratrol analogue and a preparation method and application thereof, and relates to the field of medical compounds. A structure of the cyano-containing resveratrol analogue is shown in the formula of the description; 3,5-dihydroxy-benzoic acid is mainly used as a raw material, and the cyano-containing resveratrol analogue is prepared by the following steps of methylation, reduction, brominating, Abozove rearrangement, Wittig-Hornor reaction and Knoevenegal reaction; in the preparation process of the cyano-containing resveratrol analogue, the chemical substances with lower toxicity, such as trimethylsilyl cyanide and tetrabutylammonium fluoride, are used for replacing chemicals with higher toxicity, such as sodium cyanide or potassium cyanide, to introduce cyano, so that the damage to the health of an operator is greatly decreased, and the serious harm to environments is avoided. The preparation method has the advantages that the yield is higher, the environment-friendly effect is good, and multiple types of cyano-containing resveratrol analogue with anti-cancer activity on cells can be obtained.
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Paragraph 0041; 0042; 0043
(2016/10/09)
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- Solid state red biphotonic excited emission from small dipolar fluorophores
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Dyes emitting in the solid state in the red or near-infrared range are much sought after for application in bioimaging especially if the long emission wavelength can be combined with two-photon excitation to provide unique contrast and penetration depth. In this article we present a series of small push-pull dipolar fluorophores based on 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofurane as electron accepting group. Compounds 1a-1m differ only by the number (one, two or three) and the position of methoxy groups on the electron-donor part. If these compounds are weakly emissive in dilute solution, they exhibit aggregation-induced emission properties and exciting solid state emission in the red - near infrared range very different from one compound to another highlighting the role of the number and of the position of the methoxy electron-donor groups. The solid-state properties were studied by fluorescence spectroscopy and the solid state structures were analyzed by X-ray diffraction showing the presence of a long chain of specific aggregates for the emitting species. Finally, the two-photon excitation properties were measured over the range 780-920 nm directly on the solid.
- Ipuy, Martin,Liao, Yuan-Yuan,Jeanneau, Erwann,Baldeck, Patrice L.,Bretonnière, Yann,Andraud, Chantal
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supporting information
p. 766 - 779
(2016/02/03)
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- Design and synthesis of a series of serine derivatives as small molecule inhibitors of the SARS coronavirus 3CL protease
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Synthesis of serine derivatives having the essential functional groups for the inhibitor of SARS 3CL protease and evaluation of their inhibitory activities using SARS 3CL R188I mutant protease are described. The lead compounds, functionalized serine derivatives, were designed based on the tetrapeptide aldehyde and Bai's cinnamoly inhibitor, and additionally performed with simulation on GOLD softwear. Structure activity relationship studies of the candidate compounds were given reasonable inhibitors ent-3 and ent-7k against SARS 3CL R188I mutant protease. These inhibitors showed protease selectivity and no cytotoxicity.
- Konno, Hiroyuki,Wakabayashi, Masaki,Takanuma, Daiki,Saito, Yota,Akaji, Kenichi
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supporting information
p. 1241 - 1254
(2016/03/01)
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- Nitrogen enriched mesoporous organic polymer anchored copper(ii) material: An efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems
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A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process. This journal is
- Molla, Rostam Ali,Iqubal, Md. Asif,Ghosh, Kajari,Kamaluddin,Islam, Sk. Manirul
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p. 6546 - 6559
(2015/04/14)
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- Palladium-catalyzed carbonylations of aryl bromides using paraformaldehyde: Synthesis of aldehydes and esters
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Carbonylation reactions represent useful tools for organic synthesis. However, the necessity to use gaseous carbon monoxide is a disadvantage for most organic chemists. To solve this problem, novel protocols have been developed for conducting palladium-catalyzed reductive carbonylations of aryl bromides and alkoxycarbonylations using paraformaldehyde as an external CO source (CO gas free). Hence, aromatic aldehydes and esters were synthesized in moderate to good yields.
- Natte, Kishore,Dumrath, Andreas,Neumann, Helfried,Beller, Matthias
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supporting information
p. 10090 - 10094
(2015/03/31)
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- Palladium-catalysed oxidative cross-esterification between two alcohols
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A simple palladium-catalysed oxidative cross-coupling between two different alcohols was developed. Various benzylic alcohols could couple with aliphatic alcohols in excellent yields. The use of benzyl chloride as the oxidant and the amount of aliphatic alcohol were both important for achieving the reaction selectivity.
- Xia, Jianhui,Shao, Ailong,Tang, Shan,Gao, Xinlong,Gao, Meng,Lei, Aiwen
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p. 6154 - 6157
(2015/06/08)
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- NMR methodology for complex mixture 'separation'
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Mixture 'separation' by NMR is demonstrated through the development of a pseudo 4D NMR experiment, 3D IPAP INEPT-INADEQUATE-HSQC, designed for the structural elucidation of 13C tagged compounds.
- Bell, Nicholle G. A.,Murray, Lorna,Graham, Margaret C.,Uhrin, Dusan
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supporting information
p. 1694 - 1697
(2014/02/14)
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- Pd/C-catalyzed aerobic oxidative esterification of alcohols and aldehydes: A highly efficient microwave-assisted green protocol
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We herein describe an environmentally friendly microwave-assisted oxidative esterification of alcohols and aldehydes in the presence of molecular oxygen and a heterogeneous catalysis (Pd/C, 5 mol %). This efficient and ligandless conversion procedure does not require the addition of an organic hydrogen acceptor. The reaction rate is strongly enhanced by mild dielectric heating. Furthermore, it is a versatile green procedure which generally enables the isolation of esters to be carried out by simple filtration in almost quantitative yields.
- Caporaso, Marina,Cravotto, Giancarlo,Georgakopoulos, Spyros,Heropoulos, George,Martina, Katia,Tagliapietra, Silvia
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supporting information
p. 1454 - 1461
(2014/07/22)
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- Synthesis and bioactivity of resveratrol analogues
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It has been reported that resveratrol enhanced SIRT1 expression and significantly mimicked calorie restriction by stimulating Sir2 which is the most homologic homologue of SIRT1 of mammalian. A series of novel resveratrol derivatives were designed and synthesized as novel SIRT1 activator candidates. These synthesized compounds were characterized by spectral (1H NMR) analysis and examined for their Sir2 activation against yeast parental strain-BY4743 at a concentration of 100 μM/L by Bioscreen C MBR machine. Several compounds showed a promising Sir2 activation activity compared with resveratrol. Meanwhile, the structure-activity relationships with Sirt2 activation activities were also discussed.
- Ao, Junli,Chen, Yuanmou,Xu, Xiaoling,Zhang, Xu,Yu, Yue,Yu, Peng,Hua, Erbing
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p. 2092 - 2098
(2014/06/09)
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- Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source
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A copper-catalyzed synthesis of methyl esters from aromatic aldehydes in the presence of tert-butyl hydrogen peroxide (TBHP) was developed via a radical reaction mechanism. TBHP acts not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the methyl esterification of benzylic alcohols.
- Li, Pan,Zhao, Jingjing,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 390 - 393
(2014/01/06)
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- Regioselective bromination: An approach to the D-ring of the gilvocarcins
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A method for the regioselective ortho-bromination of unsymmetrically protected 3,5-dihydroxybenzoic acid esters has been developed. The route involves protecting group optimization studies to attain high regioselectivity for the ortho-bromination. Pd-catalyzed stannation and boration were performed to construct the D-ring coupling partners for the synthesis of gilvocarcin analogs.
- Sharif, Ehesan U.,O'Doherty, George A.
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p. 1275 - 1285
(2016/11/11)
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- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
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The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
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p. 9898 - 9905
(2013/10/22)
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- A scalable process for the synthesis of (E)-pterostilbene involving aqueous Wittig olefination chemistry
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A synthetic approach toward the pharmacologically active (E)-stilbene pterostilbene is described using a Wittig reaction conducted under mildly basic, aqueous conditions. A surprising, non-intuitive difference in (E)/(Z) stereoselectivity was observed comparing the two possible isomeric Wittig routes, allowing for the development of a highly efficient process to access the title stilbene derivative through a one-pot olefination deprotection sequence.
- McNulty, James,McLeod, David
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supporting information
p. 6303 - 6306
(2013/11/06)
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- Synthesis of novel azo-resveratrol, azo-oxyresveratrol and their derivatives as potent tyrosinase inhibitors
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Ten azo compounds including azo-resveratrol (5) and azo-oxyresveratrol (9) were synthesized using a modified Curtius rearrangement and diazotization followed by coupling reactions with various phenolic analogs. All synthesized compounds were evaluated for their mushroom tyrosinase inhibitory activity. Compounds 4 and 5 exhibited high tyrosinase inhibitory activity (56.25% and 72.75% at 50 μM, respectively). The results of mushroom tyrosinase inhibition assays indicate that the 4-hydroxyphenyl moiety is essential for high inhibition and that 3,5-dihydroxyphenyl and 3,5-dimethoxyphenyl derivatives are better for tyrosinase inhibition than 2,5-dimethoxyphenyl derivatives. Particularly, introduction of hydroxyl or methoxy group into the 4-hydroxyphenyl moiety diminished or significantly reduced mushroom tryosinase inhibition. Among the synthesized azo compounds, azo-resveratrol (5) showed the most potent mushroom tyrosinase inhibition with an IC50 value of IC50 = 36.28 ± 0.72 μM, comparable to that of resveratrol, a well-known tyrosinase inhibitor.
- Song, Yu Min,Ha, Young Mi,Kim, Jin-Ah,Chung, Ki Wung,Uehara, Yohei,Lee, Kyung Jin,Chun, Pusoon,Byun, Youngjoo,Chung, Hae Young,Moon, Hyung Ryong
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supporting information
p. 7451 - 7455
(2013/02/22)
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- Alkylation of substituted benzoic acids in a continuous flow microfluidic microreactor: Kinetics and linear free energy relationships
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Alkylation of para-substituted benzoic acids by iodomethane using an organic superbase, 1,8-bis(tetramethylguanidino)naphthalene (TMGN) in DMF was chosen as a model reaction to test the quality of the control of experimental parameters in a continuous flow microfluidic reactor as it is expected to follow a perfect second order kinetics with a large dynamics by varying the substituents. These conditions may be directly used for the synthesis of natural product esters. Because TMGN reacts slowly with iodomethane, the three different mixing strategies between substrate, base and alkylating reagent were compared. The rate constants were determined for the reaction with a set of alkylating agents and in different solvents. In order to test the quality of the obtained data, temperature effect and free energy relationships, which are expected to follow predictable laws, were investigated. The kinetics vary over 6 orders of magnitude and follows a perfect Arrhenius law, allowing the determination of the energies, enthalpies, and entropies of activation. Finally, we established a Hammett linear relationship for a series of 16 substituted benzoic acids, leading to a reaction constant ρ of -0.65 for this reaction. The quality of the obtained kinetics allowed us to discuss the outliers. All kinetics were obtained with less than 0.5 mmol of substrate.
- Gholamipour-Shirazi, Azarmidokht,Rolando, Christian
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experimental part
p. 811 - 818
(2012/08/07)
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- Asymmetric total syntheses of cochliomycin A and zeaenol
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The first asymmetric total syntheses of two resorcylic acid lactones (RALs) - cochliomycin A and zeaenol - have been achieved in a divergent way. The main highlight of our strategy involves successful application of stereoselecive Keck allylation and Julia-Kocienski olefination to access an advanced intermediate, by starting from L-tartaric acid as a chiral pool compound. This intermediate is coupled with a trisubstituted benzoic acid to afford a common RCM precursor for both target molecules. Ring-closing metathesis at a late stage, followed by functional group manipulation, yielded the target molecules in an efficient way. Two resorcylic acid lactones (RALs) - cochliomycin A and zeaenol - have been synthesized for the first time by an enantiodivergent route from the common chiral pool compound L-tartaric acid. Copyright
- Jana, Nandan,Nanda, Samik
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experimental part
p. 4313 - 4320
(2012/09/22)
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- Dimerization of resveratrol trimethyl ether by phosphotungstic acid, structure confirmation of resformicol A and B
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Dimerization of the trimethyl ether of resveratrol catalyzed by phosphotungstic acid gave two tetralins and a naphthalene derivative. The structure of the tetralins was obtained by X-ray crystallography and confirms the reported stereochemical configuration of resformicol A and B.
- Davis, Matthew C.,Groshens, Thomas J.
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supporting information; experimental part
p. 3521 - 3523
(2012/08/29)
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- Synthesis, molecular modeling and biological evaluation of 2-(benzylthio)-5-aryloxadiazole derivatives as anti-tumor agents
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A series of 2-(benzylthio)-5-aryloxadiazole derivatives have been designed and synthesized, and their biological activities are also evaluated for EGFR inhibitory activity. Fourteen compounds among the twenty compounds are reported for the first time. Their chemical structures are characterized by 1H NMR, MS, and elemental analysis. Anti-proliferative and EGFR inhibition assay results have demonstrated that compound 3e shows the most potent biological activity (IC50 = 1.09 μM for MCF-7 and IC50 = 1.51 μM for EGFR). Docking simulation has been performed to position compound 3e into the EGFR active site to determine the probable binding model, with an estimated binding free energy value of -10.7 kcal/mol. Compound 3e with potent inhibitory activity in tumor growth inhibition may be a promising anti-tumor leading compound for the further research.
- Liu, Kai,Lu, Xiang,Zhang, Hong-Jia,Sun, Juan,Zhu, Hai-Liang
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scheme or table
p. 473 - 478
(2012/03/13)
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- Synthesis, biological evaluation and molecular docking studies of novel 2-(1,3,4-oxadiazol-2-ylthio)-1-phenylethanone derivatives
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In present study, a series of new 2-(1,3,4-oxadiazol-2-ylthio)-1- phenylethanone derivatives (6a-6x) as potential focal adhesion kinase (FAK) inhibitors were synthesized. The bioassay assays demonstrated that compound 6i showed the most potent activity, which inhibited the growth of MCF-7 and A431 cell lines with IC50 values of 140 ± 10 nM and 10 ± 1 nM, respectively. Compound 6i also exhibited significant FAK inhibitory activity (IC50 = 20 ± 1 nM). Docking simulation was performed to position compound 6i into the active site of FAK to determine the probable binding model.
- Zhang, Li-Rong,Liu, Zhi-Jun,Zhang, Hui,Sun, Jian,Luo, Yin,Zhao, Ting-Ting,Gong, Hai-Bin,Zhu, Hai-Liang
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scheme or table
p. 3615 - 3621
(2012/07/27)
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- Chelating carboxylic acid amides as robust relay protecting groups of carboxylic acids and their cleavage under mild conditions
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Free choice: Carboxamides of bispicolylamine are alternative protecting groups for carboxylic acids (see scheme). As a consequence of their straightforward applicability, their high chemical stability towards a broad range of conditions, and their selective cleavage under mild conditions to give either carboxylic acids or their methyl esters, this new protection method should find widespread application in the realm of organic synthesis. Copyright
- Broehmer, Manuel C.,Mundinger, Stephan,Braese, Stefan,Bannwarth, Willi
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supporting information; experimental part
p. 6175 - 6177
(2011/08/03)
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- Synthesis and biological evaluation of bilobol and adipostatin A
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Concise total synthesis of bilobol 5-pentadecenylresorcinol (1), isolated from Gingko biloba fruits, has been achieved in 10 steps with 51% overall yield from 3,5-dihydroxybenzoic acid (3). Adipostatin A (2), isolated from the fruits as well as from Streptomyces cyaneus 2299-SV1, has also been synthesized in two steps from methylated bilobol (10). The structure-activity relationship study of synthetic products was described by means of cytotoxic assay against human KB carcinoma cell lines.
- Tanaka, Ayano,Arai, Yasuhiro,Kim, Su-Nam,Ham, Jungyeob,Usuki, Toyonobu
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experimental part
p. 290 - 296
(2011/06/19)
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- 3,5,2′,4′-Tetrahydroxychalcone, a new non-purine xanthine oxidase inhibitor
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Xanthine oxidase is a key enzyme that catalyses hypoxanthine and xanthine to uric acid and the overproduction of uric acid will lead to hyperuricemia which is an important cause of gout. In the present study, three chalcone derivatives were synthesized and evaluated for inhibitory activity against xanthine oxidase in vitro. Of the compounds, only Compound 1, 3,5,2′,4′-tetrahydroxychalcone, exhibited a significant inhibitory activity on xanthine oxidase with an IC50 value of 22.5 μM. Lineweaver-Burk transformation of the inhibition kinetics data demonstrated that it was a competitive inhibitor of xanthine oxidase and Ki value was 17.4 μM. In vivo, intragastric administration of Compound 1 was able to significantly reduce serum uric acid levels and inhibited hepatic xanthine oxidase activities of hyperuricemic mice in a dose-dependent manner. Acute toxicity study in mice showed that Compound 1 was very safe at a dose of up to 5 g/kg. These results suggest that Compound 1 is a novel competitive xanthine oxidase inhibitor and is worthy of further development.
- Niu, Yanfen,Zhu, Huajie,Liu, Jia,Fan, Huafang,Sun, Ling,Lu, Wei,Liu, Xu,Li, Ling
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scheme or table
p. 161 - 166
(2012/01/11)
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- Discovery and SAR of a series of agonists at orphan G protein-coupled receptor 139
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GPR139 is an orphan G-protein coupled receptor (GPCR) which is primarily expressed in the central nervous system (CNS). In order to explore the biological function of this receptor, selective tool compounds are required. A screening campaign identified compound 1a as a high potency GPR139 agonist with an EC50 = 39 nM in a calcium mobilization assay in CHO-K1 cells stably expressing the GPR139 receptor. In the absence of a known endogenous ligand, the maximum effect was set as 100% for 1a. Screening against 90 diverse targets revealed no cross-reactivity issues. Assessment of the pharmacokinetic properties showed limited utility as in vivo tool compound in rat with a poor whole brain exposure of 61 ng/g and a brain/plasma (b/p) ratio of 0.03. Attempts to identify a more suitable analogue identified the des-nitrogen analogue 1s with a reduced polar surface area of 76.7 A2 and an improved b/p ratio of 2.8. The whole brain exposure remained low at 95 ng/g due to a low plasma exposure.
- Shi, Feng,Shen, Jing Kang,Chen, Danqi,Fog, Karina,Thirstrup, Kenneth,Hentzer, Morten,Karlsson, Jens-Jakob,Menon, Veena,Jones, Kenneth A.,Smith, Kelli E.,Smith, Garrick
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scheme or table
p. 303 - 306
(2011/06/21)
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- Total synthesis and absolute stereochemistry of seragakinone A
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(Chemical Equation Presented) Cyclic transformation: The key transformations of the asymmetric total synthesis of the marine-derived natural product seragakinone A are two N-heterocyclic carbene catalyzed benzoin cyclizations that result in the construction of two rings and a pinacol-type rearrangement to install the angular prenyl substituent.
- Takada, Akiomi,Hashimoto, Yoshimitsu,Takikawa, Hiroshi,Hikita, Katsuyoshi,Suzuki, Keisuke
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supporting information; experimental part
p. 2297 - 2301
(2011/04/16)
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- Total synthesis of (+)-papulacandin D
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A total synthesis of (+)-papulacandin D has been achieved in 31 steps, in a 9.2% overall yield from commercially available materials. The synthetic strategy divided the molecule into two nearly equal sized subunits, the spirocyclic C-arylglycopyranoside and the polyunsaturated fatty acid side-chain. The C-arylglycopyranoside was prepared in 11 steps in a 30% overall yield from triacetoxyglucal. The fatty acid side-chain was also prepared in 11 steps in a 30% overall yield from geraniol. The key strategic transformations in the synthesis are: (1) a palladium-catalyzed, organosilanolate-based cross-coupling reaction of a dimethylglucal-silanol with an electron-rich and sterically hindered aromatic iodide and (2) a Lewis-base catalyzed, enantioselective allylation reaction of a dienal and allyltrichlorosilane. A critical element in the successful execution of the synthesis was the development of a suitable protecting group strategy that satisfied a number of stringent criteria.
- Denmark, Scott E.,Kobayashi, Tetsuya,Regens, Christopher S.
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supporting information; experimental part
p. 4745 - 4759
(2010/08/06)
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- Synthesis of chiral 3-substituted phthalides by a sequential organocatalytic enantioselective aldol-lactonization reaction. Three-step synthesis of (S)-(-)-3-butylphthalide
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(Chemical Equation Presented) The development of efficient methods for the facile construction of important molecular frameworks is an important goal in organic synthesis. Chiral 3-substituted phthalides are widely distributed in a large collection of natural products with broad, potent, and potentially path-pointing biological activities. In this investigation, we have uncovered an unprecedented organocatalytic asymmetric aldol-lactonization reaction of 2-formylbenzoic esters with ketones/aldehydes for convenient construction of the enantioenriched "privileged" scaffold. As a result of the sensitive nature of substrate structures of an organocatalytic enantioselective aldol reaction, after extensive optimization of reaction conditions, catalyst L-prolinamide alcohol IV is identified as the best promoter. Interestingly, it is found that in this reaction, addition of an acid additive PhCO2H can significantly enhance reaction efficiency with use of only as low as 2.5 mol % IV for the process. Moreover, due to the sensitivity of reaction conditions toward a sequential aldol-lactonization process without affecting enantioselectivity and racemization, it is essential to remove the catalyst for the subsequent facile lactonization reaction in the presence of K 2CO3. The aldol-lactonization processes serve as a powerful approach to the preparation of synthetically and biologically important 3-substitued phthalides with a high level of enantioselectivities. A 3-step catalytic asymmetric synthesis of the natural product of 3-butylphthalide is reported.
- Zhang, Haoyi,Zhang, Shilei,Liu, Lu,Luo, Guangshun,Duan, Wenhu,Wang, Wei
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supporting information; scheme or table
p. 368 - 374
(2010/03/30)
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- Modified approach for preparing (E)-Stilbenes related to resveratrol, and evaluation of their potential immunobiological effects
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Resveratrol and closely related stilbenoids belong to the most intensively studied biologically active compounds. This interest evoked several attempts to prepare such compounds in a convenient synthetic way. Our approach allowed obtaining largely methoxystilbenes, formed as E-isomers only (using Wittig-Horner synthesis as the key step), which were further demethylated by boron tribromide. The hydroxymethoxystilbenes (e.g. pterostilbene) were prepared using isopropyl protection, later selectively deprotected by boron trichloride. The method is suitable for preparing such compounds in a large amount. Effects of the obtained stilbene derivatives on immunobiological responses triggered by lipopolysacharide and interferon-a were tested under in vitro conditions. Namely production of nitric oxide (NO) was investigated, and relation between the molecular structure and immunobiological activity was assessed.
- Smidrkal, Jan,Harmatha, Juraj,BudiSinsky, Milo,Vokae, Karel,ZIDEKc, Zdenik,Kmoniekova, Eva,Merkl, Roman,Filip, Vladimir
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scheme or table
p. 175 - 186
(2010/07/10)
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- A Simple, efficient, green, cost effective and chemoselective process for the esterification of carboxylic acids
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Carboxylic acids have been esterified under mild and solvent-free conditions in high yield and purity using the green reagents, dimethyl carbonate and diethyl carbonate, under acid catalysis. The present methodology is free of the disadvantages of base catalysis described earlier, such as high temperatures, use of autoclaves, use of the expensive DBU as base in stoichiometric amounts and the carbonate as solvent. High chemoselectivity is observed in the case of hydroxybenzoic acids.
- Rekha,Ramani, Modukuri V.,Ratnamala,Rupakalpana, Vempati,Subbaraju, Gottumukkala V.,Satyanarayana, Chava,Rao, C. Someswara
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experimental part
p. 769 - 773
(2010/04/22)
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- Inhibitory effect of a novel resveratrol derivative on nitric oxide production in lipopolysaccharide-activated microglia
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Excessive nitric oxide (NO) production by activated microglial cells has been implicated in various neurodegenerative diseases. In the present study, we found that a new resveratrol derivative, (E)-5-(3-nitrostyryl)benzene-1,3-diol (RV06), has a more potential inhibitory effect on the production of NO in LPS-activated N9 microglial cells, and the result was confirmed on primary rat microglial cells. Further studies showed that RV06 inhibited LPS-induced iNOS expression in N9 microglial cells, with no activity on direct scavenging nitric oxide radical in a cell-free environment. The results suggest that RV06 might be a potential anti-inflammatory agent or leading compound which can inhibit inflammatory responses of microglia.
- Meng,Chen,Yang,Wang,Wu, Chun Fu,Wang
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experimental part
p. 671 - 675
(2009/04/07)
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