- Electrocatalytic carboxylation of aliphatic halides at silver cathode in acetonitrile
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A simple and efficient electrocarboxylation reaction of aliphatic halides has been developed using silver as cathode, magnesium as anode and CH3CN saturated CO2 as solvent in an undivided cell. The influence of some key factors (such as the nature of electrode materials, supporting electrolytes and temperature) on this reaction was investigated. Under the optimized condition, the corresponding carboxylic acids were obtained in moderate to good yields (22-89%). The electrochemical behaviour was studied at different electrodes (Ag, Cu, Ni and Ti) by cyclic voltammetry, which showed significant electrocatalytic effect of the silver electrode towards the reductive carboxylation of aliphatic halides.
- Niu, Dong-Fang,Xiao, Li-Ping,Zhang, Ai-Jian,Zhang, Gui-Rong,Tan, Qi-Yun,Lu, Jia-Xing
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- First Kilogram-Scale Application of the Lanthanum Catalyzed Asymmetric Amination to Synthesis of the Chiral Succinimide Derivative, A Key Intermediate for the Preparation of AS-3201
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The process development of ethyl-(R)-3-amino-2,5-dioxopyrrolidine-3-carboxylate (2), the chiral intermediate for the manufacture of AS-3201 (1), is described. A practical and scalable Shibasaki asymmetric amination that generates the chiral quaternary center was developed and demonstrated on kilogram scale. A safe, convenient, and large-scale hydrogenation of the hydrazine intermediate was also developed.
- Toshima, Minoru,Watanabe, Shoji,Uchiyama, Katsuya,Takasaki, Tsuyoshi,Bhogle, Nandkumar N.,Zhao, Hang,Filios, Mike,Takahashi, Kazuhiko,Snoonian, John R.,Saranteas, Kostas
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- ALKYLIMINOMALONIC ACID AND 2-ALKYLOXAZIRIDINE-3,3-DICARBOXYLIC ACID ESTERS
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2-Alkyloxaziridine-3,3-dicarboxylic acid esters have been obtained by oxidizing alkylaminomalonic acid ester by monoperphtalic acid.The activation parameters for the inversion of the nitrogen atom have been obtained for a number of alkyliminomalonic acid and 2-alkyloxaziridine-3,3-dicarboxylic acid ester.
- Prosyanik, A.V.,Moskalenko, A.S.,Moretti, J.,Forni, A.,Torre, G.,Kostyanovskii, R.G.
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- Stereoselective formation of quaternary stereogenic centers via alkylation of α-substituted malonate-imidazolidinones
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A new stereoselective alkylation methodology is presented for formation of chiral, nonracemic quaternary centers via a chiral auxiliary protocol involving α-alkylated malonate imidazolidinones. Based on two X-ray structures of quaternized products, the diastereoselectivity observed may be rationalized via a transition-state involving an s-transC-N conformation of the C-N bond of the auxiliary, with the metal cation (K+) chelated into the malonate six-membered hole as a Z-enolate. A deprotection protocol involving ethanethiolate exchange of the imide to the corresponding thioester, followed by a standard Fukuyama reduction and a borohydride reduction, furnishes α,α-quaternized-hydroxypropionates in high ee overall.
- Bixa, Thobela,Hunter, Roger,Andrijevic, Ana,Petersen, Wade,Su, Hong,Dhoro, Francis
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- Highly efficient selective monohydrolysis of dialkyl malonates and their derivatives
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The highly efficient selective monohydrolysis of symmetric diesters has been applied to monohydrolysis of several dialkyl malonates and their derivatives. The best conditions apply 0.8-1.2 equiv of aqueous KOH with a co-solvent, THF or acetonitrile, at 0 °C. The procedure is highly practical, yielding the corresponding half-esters in high yields in a straightforward manner, without inducing decarboxylation. It was found that the selectivity tends to become higher with increased hydrophobicity.
- Niwayama, Satomi,Cho, Hanjoung,Lin, Chunlei
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- Synthesis of diverse N, O-bridged calix[1]arene[4]pyridine-C60 dyads and triads and formation of intramolecular self-inclusion complexes
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Starting from both the bridging nitrogen atom-functionalized and the upper rim-functionalized N,O-bridged calix[1]arene[4]pyridine reactants, different types of heteracalixaromatics-C60 dyads and triads of varied spacers were expediently synthesized using mainly the click reaction as the key step. By means of various spectroscopic methods, the heteracalixaromatics-C60 dyads and triads obtained have been shown to form intramolecular self-inclusion complexes rather than oligomers or polymers in solution because of a flexible spacer in between the heteracalixaromatic ring and C60 moiety. The current study, coupled with previous investigations, would provide the guideline for the construction of supramolecular fullerene motifs based on molecular design of the dyads and triads.
- Wu, Jin-Cheng,Wang, De-Xian,Huang, Zhi-Tang,Wang, Mei-Xiang
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- Practical large scale synthesis of half-esters of malonic acid
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A practical large-scale synthesis of monomethyl malonate and monoethyl malonate, which are among the most commonly applied half-esters in organic synthesis, is described, applying the highly efficient selective monohydrolysis of symmetric diesters we reported before. The optimal conditions with regard to the type of base, equivalent, co-solvents, and the reaction time have been examined for large-scale reactions. Monomethyl malonate and monoethyl malonate were obtained in high yields with near 100% purity within only half a day. The conditions of this selective monohydrolysis reaction are environmentally benign and straightforward, as it requires only water, a small proportion of a volatile co-solvent, and inexpensive reagents, and produces no hazardous by-products, and therefore the synthetic utility of this reaction in process chemistry is expected.
- Niwayama, Satomi,Cho, Hanjoung
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- Selective monoesterification of malonic acid catalyzed by boric acid
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Boric acid catalyzes the monoesterification of malonic acid, likely through a chelation mechanism that is not available to the monoester product. Under more forcing conditions, diesters form to some extent, but conditions can be optimized to favour the monoester product (56?80%). With the easily handled solid acid catalyst, these reactions can be run with excess alcohol as solvent or with stoichiometric amounts of alcohol in acetonitrile with moderate heating. CSIRO 2007.
- Levonis, Stephan M.,Bornaghi, Laurent F.,Houston, Todd A.
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- Decomposition of malonic anhydrides
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Malonic anhydrides decompose at or below room temperature, to form a ketene and carbon dioxide. Rate constants for the thermal decomposition of malonic, methylmalonic, and dimethylmalonic anhydrides were measured by NMR spectroscopy at various temperatures, and activation parameters were evaluated from the temperature dependence of the rate constants. Methylmalonic anhydride is the fastest, with the lowest δH?, and dimethylmalonic anhydride is the slowest. The nonlinear dependence on the number of methyl groups is discussed in terms of a concerted [2s + (2s + 2s)] or [2s + 2a] cycloreversion that proceeds via a twisted transition-state structure, supported by computations.
- Perrin, Charles L.,Flach, Agnes,Manalo, Marlon N.
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- Hydrogen-Bonding Assisted Catalytic Kinetic Resolution of Acyclic β-Hydroxy Amides
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Enantioenriched acyclic α-substituted β-hydroxy amides are valuable compounds in chemical, material and medicinal sciences, but their enantioselective synthesis remains challenging. A catalytic kinetic resolution (KR) of such amides with selectivity factor(s) up to >200 is developed via enantioselective acylation of primary alcohol with N-heterocyclic carbene. An enhanced selectivity for the catalytic KR process is realized using cyclic tertiary amine as base additive. Diastereomeric transition state models for the process are proposed to rationalize the origin of enantioselectivity.
- Porey, Arka,Mondal, Bhaskar Deb,Guin, Joyram
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supporting information
p. 8786 - 8791
(2021/03/17)
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- A stereocontrolled total synthesis of (±)-saframycin A
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A thirteen-step total synthesis of (±)-saframycin A from a tricyclic lactam intermediate is described. The key step of this total synthesis is the stereocontrolled construction of a pentacyclic saframycin framework via a modified Pictet-Spengler type cyclization generating a bis-carboxylic acid ester derivative, followed by decarboxylation. The cytotoxicity profiles are also presented.
- Kimura, Shinya,Saito, Naoki
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p. 4504 - 4514
(2018/07/21)
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- NOVEL COMPOUNDS AS ANTI-MYCOBACTERIALS
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The present disclosure relates to antibacterial compounds. In particular, the compounds are for inhibiting the growth of bacteria, particularly Mycobacterium tuberculosis (Mtb), and/or targeting bacteria having phospho-MurNAc-pentapeptidetranslocase. The present disclosure also relates to compositions containing these compounds and methods of the use of these compounds and compositions.
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Page/Page column 120
(2018/07/05)
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- Development of catalytic deacylative alkylations (DaA) of 3-acyl-2-oxindoles: total synthesis of meso-chimonanthine and related alkaloids
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We present an effective deacylative alkylation strategy for the construction of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudobenzylic position. A wide variety of products with quaternary centers could be accessed by employing simple Pd(0) catalysis under mild reaction conditions. Importantly, the same strategy works equally well for the dimeric 2-oxindole system, furnishing products with a vicinal quaternary center in favour of meso-isomer as the major product. Eventual application to the total syntheses of meso-chimonanthine and meso-folicanthine very well demonstrates the synthetic potential of this strategy.
- Kumar, Nivesh,Das, Mrinal Kanti,Ghosh, Santanu,Bisai, Alakesh
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supporting information
p. 2170 - 2173
(2017/02/19)
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- Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C-H and sp3 C-H bonds
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The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a 'transition-metal-free' intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon-carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N-arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction.
- Kumar, Nivesh,Ghosh, Santanu,Bhunia, Subhajit,Bisai, Alakesh
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supporting information
p. 1153 - 1169
(2016/07/06)
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- Optimizing the efficiency of antioxidants in emulsions by lipophilization: Tuning interfacial concentrations
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Optimization of the efficiency of antioxidants, AOs, in lipid-based emulsions via chemical modifications of their reactive moieties is not always possible because of the inherent experimental difficulties and because of the regulatory status of AOs. Esterification of hydrophilic AOs may be a practical, convenient, alternative approach. Here we employed a series of caffeic acid derivatives bearing the same reactive moiety but of different hydrophobicity (alkyl chain lengths of 1 to 16 carbon atoms) to investigate the effects of hydrophobicity on the oxidative stability of stripped corn oil-in-water emulsions. AO efficiency was determined by monitoring the production of primary oxidation products (conjugated dienes) with time and a non-linear, parabolic-like, variation of their efficiency with the number of C atoms in their alkyl chain, with a maximum at the C8 derivative, found. To rationalize the results, we also determined the distribution of the AOs between the oil, interfacial and aqueous regions of the same emulsions by employing a recently developed kinetic method that provides the partition constants of the AO between the oil-interfacial, PIO, and water-interfacial, PIW, regions of the intact emulsions. Values of both PIO and PIW range between 180-2000, suggesting that the transfer of the AOs to the interfacial region is spontaneous. The results indicate that the variations of both the percentage of AO in the interfacial region, % AOI, of the emulsions and the AO efficiency with the number of C atoms in the AO alkyl chain parallel each other with a maxima at the C8 derivative. The results illustrate an effective and convenient way to control lipid oxidation by modulation of the hydrophobicity (HLB) of the AOs. An increase in the alkyl chain length of the AOs promote their incorporation into the interfacial region of emulsions but only up to a critical chain length, after which a further increase makes their efficiency decrease as a consequence of the decrease in their % AOI.
- Costa, Marlene,Losada-Barreiro, Sonia,Paiva-Martins, Fátima,Bravo-Díaz, Carlos
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p. 91483 - 91493
(2016/10/09)
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- CYCLOPROPANE DERIVATIVE HAVING BACE1 INHIBITING ACTIVITY
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The present invention relates to compounds of the Formula (I) and (II): wherein each variable is as defined in the specification, pharmaceutically acceptable salts and solvates thereof, as well as use of such compounds as a BACE1 inhibitor. The compounds of the invention are useful as an agent for treating a disease induced by production, secretion and/or deposition of amyloid β protein.
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Paragraph 0187; 0193; 0196; 0200
(2014/02/15)
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- Synthesis and antitumor activity of feruloyl and caffeoyl derivatives This paper is dedicated to Prof. Wei-xiao Hu for his lifelong commitment to mentoring graduate students
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We developed two efficient protocols for the synthesis of feruloyl and caffeoyl derivatives from commercial vanillin and veratraldehyde. Pharmacological activities were assessed against a panel of human cancer cell lines in vitro. Most synthesized compounds demonstrated attractive cytotoxicity. Several new compounds demonstrated significant antiproliferative and cytotoxic activities against HeLa and Bewo tumor cell lines. In particular, 5-nitro caffeic adamantyl ester showed broad spectrum of tumor inhibition in 10 cell lines, and reduced tumor weight by 36.7% in vivo when administered at a dose of 40 mg kg-1.
- Chen, Hui-Zhen,Chen, You-Bao,Lv, Ya-Ping,Zeng, Fang,Zhang, Juan,Zhou, Yong-Lie,Li, Han-Bing,Chen, Li-Fei,Zhou, Bin-Jie,Gao, Jian-Rong,Xia, Chun-Nian
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supporting information
p. 4367 - 4371
(2015/02/06)
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- Studies on the synthesis and bioactivities of 4-amino derivatives of tetramic acid
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In order to study the potential bioactivities of 4-amino tetramic acid derivatives, the 4-amination products of pyrrolidine-2,4-diones (5) and 4-hydroxy-2-oxo-2,5-dihydro-1H-pyrrole-3-carboxylates (4) were prepared. The 4-amination of 5 took place in high yield when catalyzed by acetic acid, whereas the 4-amination of 4 was achieved through a 4-ethoxy intermediate, which was prepared by acidic etherification. Their herbicidal, fungicidal, insecticidal, and antitumor activities were tested. The bioassays showed that two of the compounds exhibited good herbicidal activity against dicot Arabidopsis thaliana at a concentration of 10 μg/mL, and one compound gave instinct fungicidal activity against Pythium sp. at a concentration of 2 μg/mL.
- Liu, Yu-Xiu,Zhao, Hua-Ping,Song, Hai-Bin,Gu, Yu-Cheng,Wang, Qing-Min
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- DDQ-mediated direct Intramolecular-Dehydrogenative-Coupling (IDC): Expeditious approach to the tetracyclic core of ergot alkaloids
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An efficient route to 2-oxindoles bearing an all-carbon quaternary center at the pseudobenzylic position has been developed via a DDQ-mediated Intramolecular-Dehydrogenative-Coupling (IDC). The methodology involves a one-pot C-alkylation of β-N-arylamido esters (7) concomitant with dehydrogenative-coupling in the presence of stoichiometric amount of DDQ. A tentative mechanistic route has been proposed for the oxidative coupling. The methodology provides a two-step entry to the ergoline structure of ergot alkaloids.
- Bhunia, Subhajit,Ghosh, Santanu,Dey, Dhananjay,Bisai, Alakesh
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supporting information
p. 2426 - 2429
(2013/06/27)
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- Synthesis of monoesters and diesters using eco-friendly solid acid catalysts - Cerium(IV) and thorium(IV) phosphates
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In the present endeavour, amorphous cerium phosphate (CP) and thorium phosphate (TP) have been synthesized by sol-gel method and also under microwave irradiation to yield CPM and TPM. CP, TP, CPM and TPM have been characterized for elemental analysis (ICP-AES), spectral analysis (FTIR), thermal analysis (TGA), X-ray diffraction studies, SEM, EDX, surface area (BET) and surface acidity (NH3-TPD). The potential use of these materials as solid acid catalysts has been explored by studying esterification as a model reaction. Monoesters such as ethyl acetate (EA), propyl acetate (PA), butyl acetate (BA), benzyl acetate (BzAc) and diesters such as diethyl malonate (DEM), diethyl succinate (DES), dibutyl phthalate (DBP), dioctyl phthalate (DOP) have been synthesized. Esterification conditions have been optimized by varying several parameters such as reaction time, catalyst amount and mole ratio of reagents. The catalytic activity has been compared and correlated with reference to surface acidity of the catalysts. It is found that catalytic activity of CPM > CP > TP M > TP. The regenerated catalysts could be reused upto two catalytic runs without significant loss in % yields of esters formed. The highlighting feature of the present work is the catalysts CPM and TPM that are synthesized in a much shorter reaction time with higher surface acidity giving good % yield of esters.
- Parangi, Tarun,Wani, Bina,Chudasama, Uma
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p. 430 - 438
(2013/09/23)
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- PROCESS FOR THE PREPARATION OF ( S ) - 3 - CYANO - 5 - METHYLHEXANOIC ACID DERIVATIVES ADN OF PREGABALIN
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The invention provides a process for the manufacture of a compound of formula (I) using an enzyme catalysed reduction of a compound of formula (lla) or llb). Compounds of formula (I) are useful for preparing pregabalin.
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(2012/03/26)
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- Intramolecular dehydrogenative coupling of sp2 C-H and sp 3 C-H bonds: An expeditious route to 2-oxindoles
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An intramolecular-dehydrogenative-coupling (IDC) using "transition- metal-free" oxidation conditions has been achieved to synthesize a variety of 2-oxindoles bearing an all-carbon quaternary stereogenic center at the benzylic position. The methodology involves a one-pot C-alkylation of β-N-arylamido esters (3, 6) with alkyl halides using potassium tert-butoxide concomitant with a dehydrogenative coupling. A radical-mediated pathway has been tentatively proposed for the oxidative process.
- Ghosh, Santanu,De, Subhadip,Kakde, Badrinath N.,Bhunia, Subhajit,Adhikary, Amit,Bisai, Alakesh
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supporting information
p. 5864 - 5867
(2013/02/22)
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- One-pot preparation of phenylpropanoid esters co-catalyzed by boric acid and piperidine
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Phenylpropanoid esters, especially those with hydroxyl and/or methoxy groups on the benzene ring, are important medicinal chemicals or intermediates. They are usually prepared by esterification of their corresponding substituted cinnamic acids with various alcohols. However, the esterification procedures often suffer from environmentally hazardous problems when sulfuric acid is used as a catalyst or suffer from unsatisfactory yields and expensive raw material when enzyme is applied as a catalyst. In this paper, a convenient one-pot process for preparing various phenylpropanoid esters from substituted benzaldehydes bearing hydroxyl and/or methoxyl groups has been developed. The alcohols react first with malonic acid catalyzed by boric acid to form monomalonate, then without separation, let the resultant mixture immediately react with the injected various substituted benzaldehydes in the presence of piperidine to afford the desired esters with moderate to good yields. Springer Science+Business Media B.V. 2011.
- Wang, Huan,Wei, Qing-Yi,Jiang, Hong,Jiang, Zhen-Hua
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experimental part
p. 207 - 213
(2012/05/20)
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- Synthesis of carbamoylacetates from α-iodoacetate, CO, and amines under Pd/light combined conditions
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We developed a novel synthetic method of carbamoylacetates from -iodoacetate, carbon monoxide, and amines under photoirradiation conditions in the presence of a Pd catalyst. This reaction likely proceeds via interplay of radical and organopalladium species. Georg Thieme Verlag Stuttgart · New York.
- Sumino, Shuhei,Fusano, Akira,Fukuyama, Takahide,Ryu, Ilhyong
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experimental part
p. 1331 - 1334
(2012/07/13)
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- Stereoselective control in the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents: Experimental investigation and theoretical rationalization
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The stereoselectivity of the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents was investigated experimentally by determination of the product stereochemistry and theoretically via DFT calculations. The results indicate that imines preferentially attack the less sterically hindered exo-side of the ketenes to generate zwitterionic intermediates. Subsequently, for cyclic imines, the intermediates undergo a conrotatory ring closure directly to produce β-lactams, while for linear imines, the imine moiety of the intermediates isomerizes to more stable intermediates, which further undergo a conrotatory ring closure to afford trans-β-lactams. The steric hindrance and the isomerization, rather than the torquoelectronic effect, play crucial roles in controlling the stereoselectivity in the practical Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents, although the unaccessible borylketene with a powerful electron acceptor group controls the stereoselectivity torquoelectronically, in theory.
- Qi, Hengzhen,Li, Xinyao,Xu, Jiaxi
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supporting information; experimental part
p. 2702 - 2714
(2011/05/19)
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- ANALOGS OF DEHYDROPHENYLAHISTINS
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Analogs of dehydrophenylahistins are disclosed as are methods for making such compounds. Compositions and methods for treating various disease conditions including cancer and non-cancer diseases associated with vascular proliferation are also disclosed.
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(2011/08/03)
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- PPAR Modulators
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1,3-dioxane derivatives are described and their use in the treatment of a disease or condition dependent on PPAR modulation, such as diabetes, cancer, inflammation, neurodegenerative disorders and infections.
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Page/Page column 20; 21; 24
(2011/08/04)
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- 1-Malonyl-1,4-dihydropyridine as a novel carrier for specific delivery of drugs to the brain
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A group of 1-malonyl-1,4-dihydropyridine derivatives were synthesized as novel carrier systems for site-specific and sustained drug delivery to the brain. Such carriers are expected to be stable against air oxidation due to the presence of the carbonyl group close to nitrogen of the dihydropyridine. These carrier systems were attached to a group of different aldehydes to afford novel quaternary pyridinium derivatives 9a-e, 11a-d, 13 and 18a-b. Reduction of the prepared quaternary pyridinium derivatives with sodium dithionite afforded a novel group of 1-malonyl-1,4-dihydropyridine chemical delivery systems (CDSs) 10a-e, 12a-d, 14 and 19a-b. The synthesized 1-malonyl-1,4-dihydropyridine CDSs were subjected to various chemical and biological investigations to evaluate their ability to cross the blood-brain barrier, and to be oxidized biologically into their corresponding quaternary derivatives. The in vitro oxidation studies showed that most of the 1-malonyl-1,4-dihydropyridine CDSs could be oxidized into their corresponding quaternary derivatives at an adequate rate. The in vivo studies showed that compounds 10c and 14 were able to cross the blood-brain barrier at detectable concentrations. Moreover, the pyridinium quaternary intermediates 9a, 9c, 13, 18a and their corresponding dihydro derivatives 10a, 10c, 14 and 19a were screened for their antidepressant activity using tail suspension behavioral despair test compared to imipramine as a reference at a dose level of 10 mg/kg. The results indicated that compounds 13, 14 and 19a induced remarkable antidepressant activity comparable to imipramine. Compounds 10a, 10c and 18a exhibited good antidepressant activity, their activities nearly equal to 92.8%, 86.7% and 90.20% of the activity of imipramine, respectively. The other derivatives 9a and 9c exhibited moderate antidepressant activity compared with imipramine.
- Hassan, Heba A.,Abdel-Aziz, Mohamed,Abuo-Rahma, Gamal El-Din A.A.,Farag, Hassan H.
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body text
p. 1681 - 1692
(2009/08/07)
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- ANALOGS OF DEHYDROPHENYLAHISTINS AND THEIR THEAPEUTIC USE
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Compounds represented by the following structure (II) are disclosed: as are methods for making such compounds. Compositions and methods for treating various disease conditions including cancer and non-cancer diseases associated with vascular proliferation are also disclosed.
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Page/Page column 23
(2008/12/08)
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- Synthesis of trans-caffeate analogues and their bioactivities against HIV-1 integrase and cancer cell lines
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Forty caffeate analogues were synthesized via a convenient method starting from vanillin with moderate to good yields. The testing of biological activity of these compounds against HIV-1 integrase indicates that four compounds: bornyl caffeate, bornyl 2-nitrocaffeate, 5-nitrocaffeic acid and 5-nitrocaffeic acid phenethyl ester (5-nitroCAPE) possess a good HIV integrase inhibitory activity, IC50 19.9, 26.8, 25.0 and 13.5 μM, respectively. Twelve caffeate analogues were tested by MTT assay on growth of human hepatocellular carcinoma BEL-7404, human breast MCF-7 adenocarcinoma, human lung A549 adenocarcinoma and human gastric cancer BCG823 cell lines, respectively. And the best result is IC50 5.5 μM for CAPE against BEL-7404.
- Xia, Chun-nian,Li, Hai-bo,liu, Feng,Hu, Wei-xiao
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supporting information; experimental part
p. 6553 - 6557
(2009/09/06)
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- SYNTHESIS OF HALF ESTERS
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A method for hydrolyzing an ester is provided. In accordance with the method, a compound A is provided which has first and second ester moieties. The compound is reacted in a liquid medium with a base having the formula MaXb,such that the first ester moiety is converted to a carboxyl moiety and the second ester moiety remains, wherein the ratio [Xk-]:[A] in the liquid medium is no greater than 1.6, and wherein k > 0.
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Page/Page column 17-22
(2009/01/24)
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- New competitive inhibitors of cytosolic (NADH-dependent) rabbit muscle glycerophosphate dehydrogenase
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We report the synthesis and biochemical evaluation of new competitive inhibitors of the cytosolic (NADH-dependent) glycerophosphate dehydrogenase. The best tested compound, phosphono-propionohydroxamic acid, with a Ki of 6 μM, might be of interest as an anti-obesity drug.
- Fonvielle, Matthieu,Therisod, Helene,Hemery, Marion,Therisod, Michel
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p. 410 - 413
(2007/10/03)
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- De novo synthesis of bacteriochlorins
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A method of making a bacteriochlorin is carried out by condensing a pair of compounds of Formula II to produce the bacteriochlorin, wherein R is an acetal or aldehyde group. The condensing may be carried out in an organic solvent, preferably in the presence of an acid. The bacteriochlorins are useful for a variety of purposes such as active agents in photodynamic therapy, luminescent compounds in flow cytometry, solar cells, light harvesting arrays, and molecular memory devices.
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Page/Page column 25
(2008/06/13)
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- One-pot preparation of caffeic acid esters from 3,4-dihydroxybenzaldehyde
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A convenient one-pot process for preparing various esters of caffeic acid from 3,4-dihydroxybenzaldehyde has been developed. The alcohols or phenols react with Meldrum's acid to form malonic acid mono-esters, which, without separating, immediately react with 3,4-dihydroxybenzaldehyde to afford the desired esters in good yield. The 1H NMR data and X-ray diffraction analyses indicate that these α,β-unsaturated esters are in trans (E) form in accord with natural esters.
- Hu, Wei-Xiao,Xia, Chun-Nian,Wang, Guo-Hong,Zhou, Wei
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p. 586 - 588
(2007/10/03)
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- Synthesis of caffeic acid esters
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A new method for the preparation of caffeic acid esters was investigated. Ten caffeic acid esters were prepared by condensation of protocatechualdehyde with malonic acid mono-esters in moderate yield. Malonic acid mono-esters were prepared from the corresponding malonate di-esters. The conformations of compounds are trans (E) form.
- Xia, Chun-Nian,Hu, Wei-Xiao
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p. 332 - 334
(2007/10/03)
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- Design, synthesis, and evaluation of aza inhibitors of chorismate mutase
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The detailed information pertaining to this panel of aza inhibitors is presented. A series of aza inhibitors (4-9) of chorismate mutase (E.C. 5.4.99.5) was designed, prepared, and evaluated against the enzyme by monitoring the direct inhibition of the chorismate, 1, to prephenate, 2, conversion. None of these aza inhibitors displayed tighter binding to the enzyme than the native substrate chorismate or greater inhibitory action than the previously reported ether analogue, 3. Furthermore, no time-dependent loss of enzyme activity was observed in the presence of the two potentially reactive aza inhibitors (7 and 9). These results in conjunction with inhibition data from a broader series of chorismate mutase inhibitors allowed a novel proposal for the mechanistic role of chorismate mutase to be developed. This proposed mechanism was computationally verified and correlated with crystallographic studies of various chorismate mutases.
- Hediger, Mark E.
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p. 4995 - 5010
(2007/10/03)
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- Hydrolysis of nitriles using an immobilized nitrilase: Applications to the synthesis of methionine hydroxy analogue derivatives
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Mild and selective hydrolysis of a large range of nitriles leading to carboxylic acids was achieved under neutral conditions by an immobilized and genetically modified enzyme preparation from Alcaligenes faecalis ATCC8750. This immobilized nitrilase has been shown to be an effective catalyst for the stereoselective hydrolysis of mandelonitrile 1a to R-(-)-mandelic acid 1c. This method is particularly useful for the production of hydroxy analogues of methionine derivatives 2c-4c that could have an interest in cattle feeding and for the transformation of compounds containing other acid- or base-sensitive groups 3a-10a. A series of aliphatic dinitriles 11a-15a was hydrolyzed to the corresponding cyano acids. The suitability of the immobilized catalyst as a robust and versatile biocatalyst is discussed, and models to account for the stereoselectivity of the enzymic hydrolysis have been proposed.
- Rey, Patrick,Rossi, Jean-Christophe,Taillades, Jacques,Gros, Georges,Nore, Olivier
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p. 8155 - 8162
(2007/10/03)
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- Design, synthesis and antimalarial activity of novel, quinoline-based, zinc metallo-aminopeptidase inhibitors
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PfA-M1, a neutral zinc aminopeptidase of Plasmodium falciparum, is a new potential target for the discovery of antimalarials. The design and synthesis of a library of 45 quinoline-based inhibitors of PfA-M1 is reported. The best inhibitor displays an IC50 of 854 nM. The antimalarial activity on a CQ-resistant strain and the specificity towards mammalian aminopeptidase N are also discussed.
- Flipo, Marian,Florent, Isabelle,Grellier, Philippe,Sergheraert, Christian,Deprez-Poulain, Rebecca
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p. 2659 - 2662
(2007/10/03)
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- Total synthesis of the amino hip analogue of didemnin A
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Disclosed is a synthetic method for the preparation of analogs of Didemnin A (1), particularly the Amino-Hip analog of Didemnin A, also known as “AipDidemnin A” (8). These compounds have the following structures:
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- Towards the rehabilitation of the Mathews' 'dry' hydrolysis reaction using microwave technology
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The Mathews' reaction is a one-pot preparation of carboxylic acids from their corresponding nitriles or amides by a 'dry' hydrolysis with phthalic acid or anhydride in the absence of water and solvent. Excellent isolated yields and selectivity (up to 99%) were attained within short reaction times (typically, 30 minutes) when the reaction was performed under microwave heating.
- Chemat, Farid
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p. 5555 - 5557
(2007/10/03)
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- Synthesis of bone-targeted oestrogenic compounds for the inhibition of bone resorption
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Syntheses have been realised for several members of a new class of potential bone resorption inhibitors consisting of steroidal oestrogenic compounds linked at the 17 position to a geminal bis(phosphonic acid) moiety through an ester linkage. The approach used has the potential to allow other biologically active compounds to be coupled to the geminal bisphosphonate unit.
- Bulman Page, Philip C,Moore, Jonathan P.G,Mansfield, Ian,McKenzie, Michael J,Bowler, Wayne B,Gallagher, James A
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p. 1837 - 1847
(2007/10/03)
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- Studies on ambiphilic radicals generated from the ester of N-hydroxy-2-thiopyridone
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Seven different α-carbethoxyalkyl radicals have been generated from Barton esters and their behaviour towards different olefins have been studied to show their philicity.
- Borah,Sarma
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p. 592 - 596
(2007/10/03)
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- A mild and convenient 'dry' hydrolysis of amides to carboxylic acids
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A one-pot preparation of carboxylic acids is described that proceeds from their corresponding amides by a 'dry' hydrolysis with phthalic anhydride in the absence of water and solvent. The method affords carboxylic acids in good yields and is applicable to a variety of substrates. (C) 2000 Elsevier Science Ltd.
- Chemat, Farid
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p. 3855 - 3857
(2007/10/03)
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- THERAPEUTIC AGENT FOR DIABETES
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A therapeutic agent for diabetes, which comprises a compound of the formula [I] wherein Xis a group of the formula wherein R4and R5are the same or different and each is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, and R6is a hydrogen atom or an amino-protecting group; R1is an optionally substituted alkyl having 1 to 5 carbon atoms, an optionally substituted alkenyl having 2 to 6 carbon atoms and the like, R2is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, R2' is a hydrogen atom, and R3is an optionally substituted alkyl having 1 to 5 carbon atoms and the like, a prodrug thereof, a pharmaceutically acceptable salt thereof, a hydrate thereof and a solvate thereof. The compound of the present invention shows superior blood sugar decreasing action on the state of hyperglycemia, but does not affect the blood sugar when it is in the normal range or in the hypoglycemic state, which means that it is free of serious side effects such as hypoglycemia. Therefore, the compound of the present invention is useful as a therapeutic drug for diabetes and also useful as a preventive of the chronic complications of diabetes.
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- An efficient method for generation of α-oxoketenes: Cycloreversion of enolized Meldrum's acid derivatives
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A series of 6-methoxy- or siloxy-4H-1,3-dioxin-4-ones was synthesized from Meldrum's acids. These dioxinones underwent 4+2 cycloreversion to methoxy- or siloxycartbonylketenes and ketones quantitatively at 20-50°C. The ketenes were characterized by IR spectroscopy as well as by trapping with t-butanol. The ready cycloreversion of these enolized Meldrum's acid derivatives strongly indicates that the anomalously high susceptibility of Meldrum's acids to nucleophilic reagents is due to the participation of carboxyketenes generated through the cycloreversion of tautomeric 6-hydroxydioxinones.
- Sato, Masayuki,Ban, Hitoshi,Kaneko, Chikara
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p. 6689 - 6692
(2007/10/03)
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- 'Dry' hydrolysis of nitriles by sodium perborate and copper salts in heterogeneous media
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Nitriles react with sodium perborate or copper salts to yield carboxylic acids under mild acidic conditions. The multiphase reaction can be carried out in the absence of solvent, water, added acid or base. The yields are good, and the nitrile group can be hydrolysed in the presence of other functional groups. A comparative study between microwave and conventional heating shows that there is no specific activation from the electromagnetic field. However, careful attention to temperature and pressure measurements in the experimental apparatus is clearly needed.
- Chemat, Farid,Poux, Martine,Berlan, Jacques
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p. 1781 - 1784
(2007/10/03)
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- Inhibition of angiotensin converting enzyme and potentiation of bradykinin by retro-inverso analogues of short peptides and sequences related to angiotensin I and bradykinin
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There is pharmacological evidence indicating that, in addition to the inhibition of angiotensin converting enzyme (ACE; EC 3.4.15.1), the potentiation of bradykinin (BK) responses may also involve the BK receptor or some binding site in the structures involved in the contractile response to this peptide. Dipeptides such as Val-Trp and some of its analogues as well as tripeptide homologues, including total and partial retroinverso peptides, were synthesized and assayed for their ability to inhibit purified guinea pig plasma ACE and to potentiate the action of BK on the isolated ileum of the same species. The peptides containing the P2-P1, P1-P'1, and P'1-P'2 inverted amide bonds inhibited ACE, were resistant to hydrolysis, and, depending on the amino acid composition, some of them potentiated the contractile response to BK while others did not. Des-[Arg1]-BK, which has an intrinsic activity at concentrations higher than 10-5 M, and the very dissimilar angiotensin I (AI) analogue [Cys5-Cys10]-angiotensin-1-(5-10)-amide, which has no detectable contractile activity, were able to inhibit ACE and potentiate BK. In contrast to these peptides, BPP(5a) and BPP(9a) from Bothrops jararaca venom, and Potentiators B and C from Agkistrodon halys blomhoffii venom were more effective as BK potentiators than as ACE inhibitors. In conclusion, we have synthesized and assayed compounds that preferentially inhibit ACE, e.g. retro-inverso tripeptides, or potentiate the response of smooth muscle to BK, e.g. snake venom peptides.
- Carmona,Juliano
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p. 1051 - 1060
(2007/10/03)
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- 'Dry' Hydrolysis of Nitriles Effected by Microwave Heating
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The preparation of carboxylic acids from their corresponding nitriles by a 'dry hydrolysis' with dicarboxylic acids, in the absence of solvent, has been investigated.The reaction proceeds very slowly at atmospheric pressure, but high yields can be obtained in much shorter reaction times under pressure.The mechanism of the reeaction has been studied and its rate constant and activation energy determined in the case of a model reaction (preparation of phenylacetic acid from benzyl cyanide with phthalic acid) under both microwave and conventional heating.No 'microwave kinetic effect' has been detected, but at high temperatures microwave heating gives better yields and selectivities.
- Chemat, Farid,Poux, Martine,Berlan, Jacques
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p. 2597 - 2602
(2007/10/02)
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- Enzyme-Catalyzed Hydrolyses of E/Z-Diastereotopic and E/Z-Diastereomeric Esters. Affect on Selectivity by Reaction Media
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PLE-catalyzed hydrolyses of different types of E/Z-diastereotopic diesters and E/Z-diastereomeric monoesters have been studied.Arylidenepropanedioic diesters are specifically hydrolyzed to the Z-half esters, whereas the de values for dialkylated methylene propanedioic diesters range between 33 and 79percent (Z).D values for the hydrolyses of the 3-methyleneazetidin-2-ones in detergent-buffer systems depend on the size of the substituent in the α-position.Diastereoselectivity of these substrates is affected by addition of the cosolvents acetonitrile and methanol.
- Schirmeister, Tanja,Otto, Hans-Hartwig
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p. 4819 - 4822
(2007/10/02)
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- Process for preparing malonic monoester
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A malonic monoester is prepared in a good yield by a single step reaction by reacting malonic acid with an alcohol in the presence of a base and an activator of malonic acid selected from the group consisting of an acyl halide or halocarbonate and an acid anhydride or dicarbonate.
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