- A porous, crystalline truxene-based covalent organic framework and its application in humidity sensing
-
Truxene is employed as a building block to successfully synthesize novel covalent organic frameworks (COFs). The condensation reaction between truxene (10,15-dihydro-5H-diindeno[1,2-a:1′,2′-c]fluorene, TX) and 1,4-phenylenediboronic acid (DBA) results in a crystalline COF with boron ester linkages (COF-TXDBA) and a surface area of 1526 m2 g-1, as confirmed by powder X-ray diffraction (PXRD) and Brunauer-Emmett-Teller (BET) surface area measurements. This is the first study where nanochannels generated by periodic COF planar layers are shown to ease the interactions of the boron ester linkages with the water molecules for efficient humidity sensing. The COF-TXDBA based % RH sensor exhibits a change of 3 orders of magnitude in impedance in the 11-98% RH range, with response and recovery times of 37 s and 42 s, respectively. The response transients measured by switching COF-TXDBA sensor back and forth in 4 loops of % RH range displays excellent reversibility of the sensor with a deviation of 2.3% in the switching process.
- Singh, Harpreet,Tomer, Vijay K.,Jena, Nityasagar,Bala, Indu,Sharma, Nidhi,Nepak, Devadutta,De Sarkar, Abir,Kailasam, Kamalakannan,Pal, Santanu Kumar
-
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Read Online
- Photoinduced Hydrocarboxylation via Thiol-Catalyzed Delivery of Formate across Activated Alkenes
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Herein we disclose a new photochemical process to prepare carboxylic acids from formate salts and alkenes. This redox-neutral hydrocarboxylation proceeds in high yields across diverse functionalized alkene substrates with excellent regioselectivity. This operationally simple procedure can be readily scaled in batch at low photocatalyst loading (0.01% photocatalyst). Furthermore, this new reaction can leverage commercially available formate carbon isotologues to enable the direct synthesis of isotopically labeled carboxylic acids. Mechanistic studies support the working model involving a thiol-catalyzed radical chain process wherein the atoms from formate are delivered across the alkene substrate via CO2?- as a key reactive intermediate.
- Alektiar, Sara N.,Wickens, Zachary K.
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supporting information
p. 13022 - 13028
(2021/09/03)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- Substituted cinnamic anhydrides act as selective inhibitors of acetylcholinesterase
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Cinnamic anhydrides have been shown to be more than reactive reagents, but they also act as inhibitors of the enzyme acetylcholinesterease (AChE). Thus, out of a set of 33 synthesised derivatives, several of them were mixed type inhibitors for AChE (from electric eel). Thus, (E)-3-(2,4-dimethoxyphenyl)acrylic anhydride (2c) showed Ki = 8.30 ± 0.94 μM and Ki′ = 9.54 ± 0.38 μM, and for (E)-3-(3-chlorophenyl)acrylic anhydride (2u) Ki = 8.23 ± 0.93 μM and Ki′ = 13.07 ± 0.46 μM were measured. While being not cytotoxic to many human cell lines, these compounds showed an unprecedented and noteworthy inhibitory effect for AChE but not for butyrylcholinesterase (BChE).
- Gie?el, Josephine M.,Serbian, Immo,Loesche, Anne,Csuk, René
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- Discovery of an Orally Bioavailable and Central Nervous System (CNS) Penetrant mGlu7 Negative Allosteric Modulator (NAM) in Vivo Tool Compound: N-(2-(1 H-1,2,4-triazol-1-yl)-5-(trifluoromethoxy)phenyl)-4-(cyclopropylmethoxy)-3-methoxybenzamide (VU6012962)
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Herein, we report the discovery of a new, orally bioavailable and CNS-penetrant metabotropic glutamate receptor 7 (mGlu7) negative allosteric modulator (NAM) that achieves exposure in cerebral spinal fluid (CSF) 2.5× above the in vitro IC50 at minimum effective doses (MEDs) of 3 mg/kg in preclinical anxiety models.
- Reed, Carson W.,Yohn, Samantha E.,Washecheck, Jordan P.,Roenfanz, Hanna F.,Quitalig, Marc C.,Luscombe, Vincent B.,Jenkins, Matthew T.,Rodriguez, Alice L.,Engers, Darren W.,Blobaum, Anna L.,Conn, P. Jeffrey,Niswender, Colleen M.,Lindsley, Craig W.
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supporting information
p. 1690 - 1695
(2019/02/24)
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- Synthesis of various arylated trifluoromethyl substituted indanes and indenes, and study of their biological activity
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A series of 1-trifluoromethyl substituted indanes and indenes bearing aryl groups in positions 1 and/or 3 of the indane core have been synthesized mainly by electrophilic cyclization and arylation of the corresponding trifluoromethylated allyl and propargyl alcohols. The distinctly lipophilic compounds thus obtained were tested against various components of human endocannabinoid system. None of the compounds displayed affinity toward CB1 or CB2 receptors. Two compounds inhibited monoacylglycerol lipase (MAGL) and three compounds showed inhibition of anandamide (AEA) uptake. The latter can be related to the low-micromolar inhibition of fatty acid amide hydrolase (FAAH) inhibition displayed by one of these compounds.
- Iakovenko, Roman O.,Chicca, Andrea,Nieri, Daniela,Reynoso-Moreno, Ines,Gertsch, Jürg,Krasavin, Mikhail,Vasilyev, Aleksander V.
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supporting information
p. 624 - 632
(2019/01/04)
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- Synthesis, in vitro and in silico evaluation of diaryl heptanones as potential 5LOX enzyme inhibitors
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A new series of diaryl heptanones (12a-q) were synthesized and their structures were confirmed by its 1H, 13C NMR and Mass spectral data. These analogs were evaluated for their anti-oxidant activity and potential to inhibit 5-lipoxygenase. Compounds 12k and 12o showed potent in vitro 5-lipoxygenase enzyme inhibitory activity with IC50 values of 22.2, 21.5 μM, which are comparable to curcumin (24.4 μM). Further they also have shown significant antioxidant activity. Molecular docking studies clearly showed correlation between binding energy and potency of these compounds.
- Meka, Bharani,Ravada, Suryachandra Rao,Muthyala, Murali Krishna Kumar,Kurre, Purna Nagasree,Golakoti, Trimurtulu
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p. 408 - 421
(2018/07/13)
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- Total Synthesis and Evaluation of B-Homo Palmatine and Berberine Derivatives as p300 Histone Acetyltransferase Inhibitors
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Palmatine and berberine, structurally similar isoquinoline alkaloids exhibiting a broad range of biological activities, were recently found to inhibit p300 histone acetyltransferase (HAT), a potential therapeutic target for treating transcriptional activator-driven malignancies and diseases. Here, we report the first total synthesis of B-homo palmatine (11a) and berberine (11b) derivatives, which were synthesized from 3,4-dimethoxybenzaldehyde (1a) and benzo[d][1,3]dioxole-5-carbaldehyde (1b) in nine steps in 13.8 and 16.9 % overall yields, respectively. A number of other new B-homo palmatine and berberine derivatives were also prepared. These derivatives display good inhibitory activity against p300 HAT; compound 12a manifests the most potent inhibition with an IC50 value of 0.42 μm. Cell-based assays revealed that 12a exhibits certain inhibitory activity against HCG27, HT1080, and Z-138 cell lines, and no visible activity towards other cancer cell lines tested, reflecting that 12a has low cytotoxicity and acts against some types of cancer cells.
- Yang, Zhongzhen,Zhang, Yong,Chen, Xin,Li, Weijian,Li, Guo-Bo,Wu, Yong
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p. 1041 - 1052
(2018/03/06)
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- Pd-Catalyzed β-C(sp3)?H Arylation of Propionic Acid and Related Aliphatic Acids
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A generally applicable Pd-catalyzed protocol for the β-C(sp3)?H arylation of propionic acid and related α-branched aliphatic acids is reported. Enabled by the use of N-acetyl-β-alanine as ligand our protocol delivers a broad range of arylation products. Notably, the highly challenging substrate, propionic acid, which lacks any acceleration through the Thorpe–Ingold effect, can be employed as substrate with synthetically useful yields. Furthermore, the scalability and synthetic applicability of the protocol are demonstrated.
- Ghosh, Kiron K.,van Gemmeren, Manuel
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supporting information
p. 17697 - 17700
(2017/12/07)
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- A 3,4-dimethoxy-method for preparation of propionic acid (by machine translation)
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The invention belongs to the technical field of chemical synthesis, in particular relates to a key intermediate donepezil hydrochloride 3,4-dimethoxy-method for preparation of propionic acid. The method comprises the following steps: to 3,4-dimethoxy-benzaldehyde as a raw material, sodium in ethanol and ethyl acetate under the action of the reaction, the intermediate 3,4-di-methoxy cinnamic acid ethyl ester; 3,4-di-methoxy cinnamic acid ethyl ester hydrolysis under alkaline conditions after the, re-hydrogenation reduction to obtain 3,4-dimethoxy-propionic acid. The preparation method of this invention has is friendly to the environment, the product has high purity, high yield, low cost of raw materials, and the like. (by machine translation)
- -
-
Paragraph 0005; 0025
(2016/11/14)
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- Xylochemistry - Making Natural Products Entirely from Wood
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The first total synthesis of the dimeric berberine alkaloid ilicifoline (ilicifoline B) is reported. Its carbon skeleton is constructed from ferulic acid, veratrole, and methanol. The synthesis reported herein employs starting materials solely derived from wood. The natural product is thus constructed entirely from renewable resources. The same strategy is applied to a formal total synthesis of morphinan alkaloids. The use of wood-derived building blocks (xylochemicals) instead of the conventional petrochemicals represents a sustainable alternative to classical synthetic approaches.
- Stubba, Daniel,Lahm, Günther,Geffe, Mario,Runyon, Jason W.,Arduengo, Anthony J.,Opatz, Till
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supporting information
p. 14187 - 14189
(2016/01/25)
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- (-)-Tarchonanthuslactone: Design of New Analogues, Evaluation of their Antiproliferative Activity on Cancer Cell Lines, and Preliminary Mechanistic Studies
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Natural products containing the α,β-unsaturated δ-lactone skeleton have been shown to possess a variety of biological activities. The natural product (-)-tarchonanthuslactone (1) possessing this privileged scaffold is a popular synthetic target, but its biological activity remains underexplored. Herein, the total syntheses of dihydropyran-2-ones modeled on the structure of 1 were undertaken. These compounds were obtained in overall yields of 17-21 % based on the Keck asymmetric allylation reaction and were evaluated in vitro against eight different cultured human tumor cell lines. We further conducted initial investigation into the mechanism of action of selected analogues. Dihydropyran-2-one 8 [(S,E)-(6-oxo-3,6-dihydro-2H-pyran-2-yl)methyl 3-(3,4-dihydroxyphenyl)acrylate], a simplified analogue of (-)-tarchonanthuslactone (1) bearing an additional electrophilic site and a catechol system, was the most cytotoxic and selective compound against six of the eight cancer cell lines analyzed, including the pancreatic cancer cell line. Preliminary studies on the mechanism of action of compound 8 on pancreatic cancer demonstrated that apoptotic cell death takes place mediated by an increase in the level of reactive oxygen species. It appears as though compound 8, possessing two Michael acceptors and a catechol system, may be a promising scaffold for the selective killing of cancer cells, and thus, it deserves further investigation to determine its potential for cancer therapy. Fighting the big C: We describe the synthesis of a new family of analogues based on the scaffold of the natural product (-)-tarchonanthuslactone; these compounds were evaluated in vitro against tumor cell lines. We further conducted an initial investigation into the mechanism of action, including the inhibition of phosphatases and glutathione-S-transferase and the production of reactive oxygen species.
- Toneto Novaes, Luiz Fernando,Martins Avila, Carolina,Pelizzaro-Rocha, Karin Juliane,Vendramini-Costa, Débora Barbosa,Pereira Dias, Marina,Barbosa Trivella, Daniela Barreto,Ernesto De Carvalho, Jo?o,Ferreira-Halder, Carmen Veríssima,Pilli, Ronaldo Aloise
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p. 1687 - 1699
(2015/10/06)
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- Minimizing Aryloxy Elimination in RhI-Catalyzed Asymmetric Hydrogenation of β-Aryloxyacrylic Acids using a Mixed-Ligand Strategy
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The first example of efficient asymmetric hydrogenation of challenging β-aryloxyacrylic acids was realized using a RhI-complex based on the heterocombination of a readily available chiral monodentate secondary phosphine oxide (SPO) and an achiral monodentate phosphine ligand as the catalyst. Excellent enantioselectivities (92->99% ee) were achieved for a wide variety of chiral β-aryloxypropionic acids with minor aryloxy elimination in most cases. The resultant products were readily transformed into biologically active compounds through simple synthetic manipulations.
- Li, Yang,Wang, Zheng,Ding, Kuiling
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supporting information
p. 16387 - 16390
(2015/11/09)
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- Synthesis, characterization and nonlinear optical studies of novel blue-light emitting room temperature truxene discotic liquid crystals
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A new series of discotic liquid crystals based on a truxene core has been synthesized to study the structure-property relationship in view of the self-assembling property and their linear and nonlinear optical properties. All these branched alkyl chain truxene derivatives show a mesogenic property in a columnar hexagonal fashion at room temperature which is studied by a combination of different techniques. The newly synthesized truxene discotic 7a possesses a clearing temperature of 117 °C, one of the lowest clearing temperatures known in truxene discotic liquid crystals. We have discovered that the introduction of branching near to the core even in a small alkyl chain drastically reduces the isotropic temperature. Due to their C3 symmetry and their large first hyperpolarizability, these truxene derivatives show long-lived emissions in the solution state at room temperature. We also report large effective three-photon absorption in these materials under nanosecond laser pulse excitation at 532 nm, which makes them suitable candidates for optical limiting applications.
- Vinayakumara,Kumar, Manish,Sreekanth,Philip, Reji,Kumar, Sandeep
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p. 26596 - 26603
(2015/03/30)
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- PYRIMIDINE DERIVATIVES FOR THE TREATMENT OF VIRAL INFECTIONS
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This invention relates to pyrimidine derivatives, processes for their preparation, pharmaceutical compositions, and their use in treating viral infections such as HCV or HBV.
- -
-
Paragraph 0126; 0127; 0128
(2014/03/21)
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- Synthesis and anticancer activity of some 2-[3/4-(2-substituted phenyl-2-oxoethoxy)benzylidene]-6-substituted-2,3-dihydro-1H-inden-1-one derivatives
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The synthesis of 2-[3/4-(2-substituted phenyl-2-oxoethoxy)benzylidene]-6- substituted-2,3-dihydro-1H-inden-1-one derivatives and the investigation of their anticancer activity were studied. 2-(3- or 4-Hydroxybenzylidene)-6- substituted-2,3-dihydro-1H-inden-1-ones were reacted with suitable 2-bromoacetophenones to give 2-[3/4-(2-substituted phenyl-2-oxoethoxy) benzylidene]-6-substituted-2,3-dihydro-1H-inden-1-one derivatives. The structure elucidation of the synthesised compounds was performed by IR, 1H-NMR, mass spectroscopic data and elemental analyses. The anticancer screening was carried out in National Cancer Institute (NCI), USA. Notable activity was obtained for some compounds.
- Gundogdu-Karaburun, Nalan,Karaburun, Ahmet Cagri,Demirayak, Seref,Kayagil, Ismail,Yurttas, Leyla
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p. 578 - 585
(2014/05/20)
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- Improved synthesis of natural ester sintenin and its analogues via Wittig reaction
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The synthesis of a cytotoxic natural ester sintenin (7a) and twenty eight of its analogues including nitrogen-containing heterocyclic indole moiety (7b-7t), saturated (10a-10d) and unsaturated (10e-10h) amides were carried out by convenient route via one-pot Wittig reaction in aqueous medium with improved yield. A systematic structure activity relationship of sintenin ester was designed by chemically modified derivatives in order to get better cytotoxicity.
- Sharma, Mukul,Rajesh, U. Chinna,Rawat, Diwan S.
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p. 1853 - 1860
(2014/01/17)
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- PYRIMIDINE DERIVATIVES FOR THE TREATMENT OF VIRAL INFECTIONS
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This invention relates to pyrimidine derivatives, processes for their preparation, pharmaceutical compositions, and their use in treating viral infections such as HCV or HBV.
- -
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Page/Page column 25
(2012/10/18)
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- Raney nickel-catalyzed hydrogenation of unsaturated carboxylic acids with sodium borohydride in water
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A mild, selective, and green method for the reduction of unsaturated carboxylic acids with sodium borohydride-Raney nickel (W6) system in water is reported. This method is practical and safe and avoids use of organic solvents. Taylor & Francis Group, LLC.
- Rao, Gopal Krishna,Gowda, Narendra B.,Ramakrishna, Ramesha A.
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experimental part
p. 893 - 904
(2012/02/01)
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- NOVEL DXR INHIBITORS FOR ANTIMICROBIAL THERAPY
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The present invention generally concerns particular methods and compositions for antimicrobial therapy. In particuarl embodiments, the compositions target DXR. In specific embodiments, the compositions are electron-deficient heterocyclic rings.
- -
-
Page/Page column 67; 72
(2011/05/05)
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- FLAVAN-3-OL CONTAINING FOODSTUFFS
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The use of a compound for the reduction or elimination of bitterness caused by flavan-3-ols is provided. Compositions having greater than 0.01 wt % flavan-3-ols and that comprise an effective amount of the compound are also provided. The compound conforms to the general formula (I): wherein R1 represents C2-C3 saturated or unsaturated divalent hydrocarbon radical, n is an integer from 0 to 3, and each X is independently selected from C1-C3 alkyloxy and OH; and wherein if n is 0 then R1 is C3 saturated divalent hydrocarbon radical or C2-C3 unsaturated divalent hydrocarbon radical; and wherein if n is greater than 0 then the compound has formula (II)
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- Tyrosinase inhibitory activities of cinnamic acid analogues
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The aim of this study was to show how tyrosinase inhibitory activity is correlated with the structure of cinnamic acid derivatives. We synthesized cinnamic acid derivatives, and investigated their tyrosinase inhibitory and DPPH radical scavenging activities. The results show that reduction of C=C double bonds and the substituent group of cinnamic acid derivatives have an effect on antioxidant activity and tyrosinase inhibitory activity. Among these compounds, compounds 2, 6 and 6a showed a potent tyrosinase inhibitory activity with IC50 (50% inhibitory concentration) values of 115.6 μM, 114.9 μM and 195.7 μM, respectively. The results obtained provide a useful clue for the design and development of new tyrosinase inhibitors.
- Takahashi,Miyazawa, Mitsuo
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experimental part
p. 913 - 918
(2011/08/06)
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- Coordination chemistry based approach to lipophilic inhibitors of 1-deoxy-D-xylulose-5-phosphate reductoisomerase
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1-Deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) in the non-mevalonate pathway found in most bacteria is a validated anti-infective drug target. Fosmidomycin, a potent DXR inhibitor, is active against Gram-negative bacteria. A coordination chemistry and structure based approach was used to discover a novel, lipophilic DXR inhibitor with an IC50 of 1.4 μM. It exhibited a broad spectrum of activity against Gram-negative and -positive bacteria with minimal inhibition concentrations of 20-100 μM (or 3.7-19 μg/mL).
- Deng, Lisheng,Sundriyal, Sandeep,Rubio, Valentina,Shi, Zheng-Zheng,Song, Yongcheng
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supporting information; experimental part
p. 6539 - 6542
(2010/04/04)
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- A novel and efficient synthesis of dihydrexidine
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An efficient synthesis of the dopamine D1 selective full agonist dihydrexidine has been achieved in high yields and requiring no chromatographic separations via a facilitated intramolecular Henry cyclization of a (nitropropyl)benzophenone and subsequent diastereomerically selective reduction of the resulting tricyclic ni- troalkene. Georg Thieme Verlag Stuttgart.
- Cueva, Juan Pablo,Nichols, David E.
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experimental part
p. 715 - 720
(2009/09/06)
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- Highly chemoselective metal-free reduction of tertiary amides
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This communication describes the chemoselective metal-free reduction of tertiary amides to the corresponding amines. Hantzsch ester is used as a mild reducing agent for the reduction of trifluoromethanesulfonic anhydride activated amides providing the tertiary amines with high functional group tolerance. Copyright
- Barbe, Guillaume,Charette, Andre B.
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- Palladium-catalyzed cross-coupling reactions in one-pot multicatalytic processes
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Palladium-catalyzed cross-coupling reactions have been investigated in multicatalytic processes to synthesize disubstituted alkenes and alkanes from carbonyl derivatives. The use of copper-catalyzed methylenation reactions is the key starting reaction to produce terminal alkenes which are not isolated, but submitted to further structure elongation. Not only is the isolation of the alkene intermediate unnecessary, but also the copper catalyst is a beneficial cocatalyst in the palladium-catalyzed cross-coupling reactions. The desired products are thus typically obtained in higher yields using this one-pot approach. We have used these processes to synthesize hydroxylated (E)-stilbenoids, which are known chemopreventive and chemotherapeutic agents, odorant-substituted indanes, and non-natural amino acids, such as homophenylalanine.
- Lebel, Helene,Ladjel, Chehla,Brethous, Lise
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p. 13321 - 13326
(2008/09/17)
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- Solid-supported green synthesis of substituted hydrocinnamic esters by focused microwave irradiation
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An efficient chemoselective hydrogenation protocol for substituted cinnamic esters is developed for the synthesis in quantitative yield of corresponding bioactive dihydrocinnamic esters with solid-supported palladium chloride/ammonium formate (cat.) in HCOOH/H2O 1:2 as a hydrogenating agent under focused-microwave irradiation for 10 min.
- Kumar, Vinod,Sharma, Anuj,Sinha, Arun K.
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p. 483 - 495
(2007/10/03)
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- A chemoselective hydrogenation of the olefinic bond of α,β- unsaturated carbonyl compounds in aqueous medium under microwave irradiation
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A microwave-assisted mild and ecofriendly catalytic transfer hydrogenation process was developed to reduce various α,β-unsaturated carbonyl compounds into the corresponding saturated carbonyl compounds in the presence of silica-supported palladium chloride as catalyst and a combination of MeOH/HCOOH/H2O (1:2:3) as hydrogen source within 22-55 minutes in moderate to excellent yields with 100% chemoselectivity.
- Sharma, Anuj,Kumar, Vinod,Sinha, Arun K.
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p. 354 - 360
(2007/10/03)
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- The synthesis of Sintenin, a new cytotoxic ester from Piper sintenense
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A first short synthesis of Sintenin 1 has been accomplished starting from 3,4-dimethoxybenzaldehyde 2 utilizing Knoevenagal condensation and catalytic hydrogenation using Pd/C as key reactions, in almost quantitative yield. The identity with the naturally occurring compound Sintenin was established on the basis of 1H NMR and 13C NMR data.
- Sharma,Sharma,Rathee, Raman
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p. 938 - 939
(2007/10/03)
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- Application of ionic liquids in palladium(II) catalyzed homogenous transfer hydrogenation
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The first application of palladium(II) catalyzed homogenous transfer hydrogenations in ionic liquids is described. Cinnamic acid and its derivatives were reduced in high yields under mild conditions using ammonium formate as hydrogen donor.
- Baán, Zoltán,Finta, Zoltán,Keglevich, Gy?rgy,Hermecz, István
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p. 6203 - 6204
(2007/10/03)
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- A Rapid and Efficient Microwave-Assisted Synthesis of Substituted 3-Phenylpropionic Acids from Benzaldehydes in Minutes
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A convenient, inexpensive, and efficient synthesis of 3-phenylpropionic acids (1a-1f) by reacting benzaldehyde (2a-2f) and malonic acid in acetic acid and piperidine into cinnamic acid (3a-3f) in 77 to 89% followed by its reduction with PdCl2 in the biphase of formic acid and aqueous sodium hydroxide is reported under microwave irradiation which utilizes short reaction time ranging 5 to 7 min to provide 1a-1f in moderate to high yield (69-86%) depending upon methoxy, methylenedioxy, and hydroxy groups present at the phenyl ring.
- Sharma, Anuj,Joshi, Bhupendra P.,Sinha, Arun K.
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p. 1186 - 1187
(2007/10/03)
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- Pd black deposited on polypropylene sheet as a highly selective catalyst for hydrogenation of alkenes
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A catalyst deposited on a polypropylene sheet having an activity of almost the same level as commercially available Pd black and capable of promoting hydrogenolysis-free hydrogenation was developed.
- Maki, Shojiro,Okawa, Makiko,Makii, Toshimichi,Hirano, Takashi,Niwa, Haruki
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p. 3717 - 3721
(2007/10/03)
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- Hydrogenolysis-free hydrogenation by Pd black powder catalyst
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A new general method of hydrogenolysis-free hydrogenation using a commercially available Pd black powder catalyst has developed.
- Maki,Okawa,Matsui,Hirano,Niwa
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p. 1590 - 1592
(2007/10/03)
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- Effect of solvent and hydrogen during selective hydrogenation
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Described is the solvent effect for the chemoselective hydrogenation of alkenes having a benzyloxy group (Bn-O-) using a hydrogenation system employing atomic hydrogen permeating through a Pd sheet electrode.
- Maki, Shojiro,Harada, Yasuhiro,Matsui, Ryo,Okawa, Makiko,Hirano, Takashi,Niwa, Haruki,Koizumi, Megumi,Nishiki, Yoshinori,Furuta, Tsuneto,Inoue, Hiroshi,Iwakura, Chiaki
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p. 8323 - 8327
(2007/10/03)
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- Dopamine D3 receptor antagonists. 1. Synthesis and structure-activity relationships of 5,6-Dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans
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5,6-Dimethoxy-2-(N-dipropyl)-aminoindan (3, PNU-99194A) was found to be a selective dopamine D3 receptor antagonist with potential antipsychotic properties in animal models. To investigate the effects of nitrogen substitution on structure- activity relationships, a series of 5,6-dimethoxy-N-alkyl- and N-alkylaryl-substituted 2-aminoindans were synthesized and evaluated in vitro for binding affinity and metabolic stability. The results indicate that substitution at the amine nitrogen of the 2-aminoindans is fairly limited to the di-N-propyl group in order to achieve selective D3 antagonists. Thus, combinations of various alkyl groups were generally inactive at the D3 receptor. Although substitution with an N-alkylaryl or N-alkylheteroaryl group yields compounds with potent D3 binding affinity, the D2 affinity is also enhanced, resulting in a less than 4-fold preference for the D3 receptor site, and no improvements in metabolic stability were noted. A large-scale synthesis of the D3 antagonist 3 has been developed that has proven to be reproducible with few purification steps. The improvements include the use of 3,4-dimethoxybenzaldehyde as a low-cost starting material to provide the desired 5,6-dimethoxy-1-indanone 5c in good overall yield (65%) and the formation of a soluble silyl oxime 17 that was reduced efficiently with BH3·Me2S. The resulting amino alcohol was alkylated and then deoxygenated using a Lewis acid and Et3SiH to give the desired product 3 in good overall yield of (~65%) from the indanone 5c.
- Haadsma-Svensson,Cleek,Dinh,Duncan,Haber,Huff,Lajiness,Nichols,Smith,Svensson,Zaya,Carlsson,Lin
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p. 4716 - 4732
(2007/10/03)
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- Arylamide inhibitors of HIV-1 integrase
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Based on data derived from a large number of HIV-1 integrase inhibitors, similar structural features can be observed, which consist of two aryl units separated by a central linker. For many inhibitors fitting this pattern, at least one aryl ring also requires orth obis-hydroxylation for significant inhibitory potency. The ability of such catechol species to undergo in situ oxidation to reactive quinones presents one potential limitation to their utility. In an effort to address this problem, a series of inhibitors were prepared which did not contain ortho bishydroxyls. None of these analogues exhibited significant inhibition. Therefore an alternate approach was taken, whose aim was to increase potency rather than eliminate catechol substructures. In this latter study, naphthyl nuclei were utilized as aryl components, since a previous report had indicated that fused bicyclic rings may afford higher affinity relative to monocyclic phenyl-based systems. In preliminary work with monomeric units, it was found that the 6,7-dihydroxy- 2-naphthoic acid (17) (IC50 = 4.7 μM) was approximately 10-fold more potent than its 5,6-dihydroxy isomer 19 (IC50 = 62.4 μM). Of particular note was the dramatic difference in potency between free acid 17 and its methyl ester 21 (IC50 > 200 μM). The nearly total loss of activity induced by esterification strongly indicates that the free carboxylic -OH is important for high potency of this compound. This contrasts with the isomeric 5,6-dihydroxy species 19, where esterification had no effect on inhibitory potency (23, IC50 = 52.7 μM). These data provide evidence that the monomeric 6,7- and 5,6-dihydroxynaphthalenes may be interacting with the enzyme in markedly different fashions. However, when these naphthyl nuclei were incorporated into dimeric structures, significant enhancements in potencies each relative to the monomeric acids were observed, with bis-6,7- dihydroxy analogue 49 and bis-5,6-dihydroxy analogue 51 both exhibiting approximately equal potencies (IC50 values of 0.81 and 0.11 μM, respectively).
- Zhao, He,Neamati, Nouri,Mazumder, Abhijit,Sunder, Sanjay,Pommier, Yves,Burke Jr., Terrence R.
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p. 1186 - 1194
(2007/10/03)
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- Involvement of the β-diketone moiety in the antioxidative mechanism of tetrahydrocurcumin
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We examined the inhibitory effects of curcumin and tetrahydrocurcumin (THC), one of the major metabolites of curcumin, on the lipid peroxidation of erythrocyte membrane ghosts induced by tert-butylhydroperoxide. The results demonstrated that THC showed a greater inhibitory effect than curcumin. To investigate the mechanism of antioxidative activity, we examined the effects of several inhibitors, such as antioxidant enzymes, hydroxyl radical scavengers, 1O2 quencher, and chelating agents for metal ions. Given that all inhibitors failed to inhibit membrane peroxidation, THC must scavenge radicals such as tert-butoxyl radical and peroxyl radical. To clarify the antioxidative mechanism of THC, in particular the role of the β-diketone moiety, dimethylated THC was incubated with peroxyl radicals generated by thermolysis of 2,2'-azobis(2,4-dimethylvaleronitrile). Four oxidation products were detected, three of which were identified as 3,4-dimethoxybenzoic acid, 3',4'-dimethoxyacetophenone, and 3-(3,4-dimethoxyphenyl)-propionic acid. The fourth oxidation product seems to be an unstable intermediate, and its detailed structure has not been determined. These results suggest that the β-diketone moiety of THC must exhibit antioxidative activity by cleavage of the C-C bond at the active methylene carbon between two carbonyls in the β-diketone moiety. Because THC is one of the major metabolites of curcumin, it may also exhibit the same physiological and pharmacological properties as the active form of curcumin in vivo by means of the β-diketone moiety as well as phenolic hydroxy groups.
- Sugiyama, Yasunori,Kawakishi, Shunro,Osawa, Toshihiko
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p. 519 - 525
(2007/10/03)
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- Simple, safe, large scale synthesis of 5-arylmethyl-2,2-dimethyl-1,3-dioxane-4,6-diones and 3-aryl-propanoic acids
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Reaction of aryl aldehydes with Meldrum's acid 2 in the presence of formic acid and triethylamine with 5-arylmethyl Meldrum's acid derivatives 4 at room temperature, whereas at 80-100°C 3-arylpropanoic acids 5 are formed.
- Toth,Kover
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p. 3067 - 3074
(2007/10/03)
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- Process for the preparation of carboxylic acids and derivatives of them
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The subject matter of the invention is a process for the preparation of carboxylic acids and derivatives of them of the general formula STR1 wherein R means hydrogen, or a C1-4 alkyl or a (C1-5 alkoxy)carbonyl group, R1 is as defined in claim 1, R7 stands for hydrogen or a C1-7 alkyl group and R8 means hydrogen or a carboxyl group, by reacting a 1,3-dioxane-4,6-dione derivative of the general formula STR2 wherein R9 stands for a C1-4 alkyl group or a phenyl group, optionally monosubstituted by halogen and R10 stands for hydrogen or a C1-5 alkyl group or R9 and R10 together form a pentamethylene group, and an aldehyde or ketone of the general formula STR3 in the presence of formic acid.
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- Process for the preparation of carboxylic acids and derivatives of them
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The subject matter of the invention is a process for the preparation of carboxylic acids and derivatives of them of the general formula wherein Rmeans hydrogen, or a C1 4alkyl or a (C1 5alkoxy)carbonyl group, R1is as defined in claim 1, R7stands for hydrogen or a C1 7alkyl group and R8means hydrogen or a carboxyl group, by reacting a 1,3-dioxane-4,6-dione derivative of the general formula wherein R9stands for a C1 4alkyl group or a phenyl group, optionally monosubstituted by halogen and R10stands for hydrogen or a C1 5alkyl group or R9 and R10together form a pentamethylene group, and an aldehyde or ketone of the general formula in the presence of formic acid and of [a] amine(s) and, if desired, of an alcohol of the general formula, , R7 - OH VI,, , wherein R7is a C1 7alkyl group, at a temperature of 20 to 140°C, and/or, reducing an unsaturated 1,3-dioxane-4,6-dione derivative of the general formula and/or, a 1,3-dioxane-4,6-dione derivative of the general formula with formic acid in the presence of [a] amine(s) and, if desired, of an alcohol as above defined.
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- CINNAMIC ACID BRIDGES BETWEEN CELL WALL POLYMERS IN WHEAT AND PHALARIS INTERNODES
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A method has been devised for the quantitative determination of cinnamic acids participating in ester-ether bridges between cell wall polymers based on the different reactivities of free carboxylic acids and their esters towards borohydride reductants and the different susceptibilities of cinnamic acid ester and benzyl ether linkages to alkaline treatments.Lignin-poylsaccharide containing fractions extracted with dioxane-H2O from cell walls of wheat (Triticum aestivum) and phalaris (phalaris aquatica) internodes are hydrogenated using a Pd/C catalyst at room temperature to convert cinnamic acids to their corresponding dihydrocinnamic acids.The sample is subsequently reduced with LiBH4 in ether-toluene to convert ester-linked dihydrocinnamates to their corresponding alcohols, hydrolysed with 4 M NaOH at 170 deg, and the dihydrocinnamic acid derivatives released from their etherified forms determined by GC.Using model compounds it was shown that these reactions proceeded quantitatively.The results indicate that all of the etherified ferulic acid in the dioxane-H2O-soluble fractions of walls of wheat and phalaris internodes is also ester-linked.It has been calculated that there are nine to 10 ferulic acid ester-ether bridges for every 100 C6-C3 lignin monomers. p-Coumaric acid is not involved in ester-ether bridges. Key Word Index - Triticum aestivum; Phalaris aquatica; Gramineae; lignin; polysaccharide; p-coumaric acid; ferulic acid; esterified cinnamic acid; etherified cinnamic acid.
- Lam, Thi Bach Tuyet,Iiyama, Kenji,Stone, Bruce A.
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p. 1179 - 1184
(2007/10/02)
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- Method of inhibiting sweetness
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The sweetness of an ingestible product containing a sweetening sugar or sugar alcohol in large quantities can be reduced by incorporating therein a sweetness-reducing amount of at least one compound of the general formula: STR1 in which m represents 0 or 1, and when m represents 0, n represents 1, 2 or 3, and p represents 1, 2, 3 or 4, and when m represents 1, n represents 1 or 2 and p represents 0, 1, 2, 3 or 4; the substituents R, which may be the same or different, each represent a lower alkoxy group, e.g. with 1 to 5 carbon atoms, phenoxy group or a lower alkyl or trifluoromethyl group; and/or two substituents R together represent an aliphatic chain linked to the phenyl ring at two positions, either directly or via an oxa-group, e.g. an alkylenedioxy, alkenylenedioxy, alkylenoxy or alkenylenoxy group; and/or one substituent R represents a hydroxy group while at least one other substituent R represents an alkoxy group; and X+ represents a physiologically acceptable cation.
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