- Ruthenium-p-cymene Complex Side-Wall Covalently Bonded to Carbon Nanotubes as Efficient Hybrid Transfer Hydrogenation Catalyst
-
A half-sandwich ruthenium-p-cymene organometallic complex has been immobilized at Single Walled Carbon Nanotubes (SWNT) sidewalls through a stepwise covalent chemistry protocol. The introduction of amino groups by means of diazonium-chemistry protocols leads the grafting at the outer walls of the nanotubes. This hybrid material is active in the transfer hydrogenation of ketones to yield alcohols, using as hydrogen source 2-propanol. SWNT?NH2?Ru presents a broad scope, performing the reaction under aerobic conditions and can be recycled over 9 consecutive reaction runs without losing activity or leaching ruthenium out. Comparison of the activity with related homogeneous catalysts reveals an improved performance due to the covalent bond between the metal and the material, achieving turnover frequencies as high as 192774 h?1.
- Blanco, Matías,Cembellín, Sara,Agnoli, Stefano,Alemán, José
-
p. 5156 - 5165
(2021/11/05)
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- Diastereoselective Diboration of Cyclic Alkenes: Application to the Synthesis of Aristeromycin
-
The Pt-catalyzed diboration of cyclic alkenes is extended to unsaturated heterocycles and bicyclic compounds and can be accomplished in a diastereoselective fashion. The optimal procedures, substrate scope, and diastereoselectivity were investigated, and examples employing both homogeneous and heterogeneous catalysis were examined. Lastly, application to the construction of the nucleoside analog (±)-aristeromycin was conducted.
- Vendola, Alex J.,Allais, Christophe,Dechert-Schmitt, Anne-Marie R.,Lee, James T.,Singer, Robert A.,Morken, James P.
-
supporting information
p. 2863 - 2867
(2021/05/05)
-
- Cyclopentadiene fuels
-
A method for making cyclopentadiene fuels comprising producing cyclopent-2-en-1-one or a mixture of cyclopent-2-en-1-one from a bio-based source. The cyclopent-2-en-1-one or the mixture of cyclopent-2-en-1-one is hydrogenated, thereby forming cyclopent-2-en-1-ol or a mixture of cyclopent-2-en-1-ol. The cyclopent-2-en-1-ol or the mixture of cyclopent-2-en-1-ol is dehydrated with a dehydrating agent, thereby forming cyclopentadiene or a mixture of cyclopentadiene. The cyclopentadiene or mixture of cyclopentadiene is converted to dicyclopentadiene or dihydrodicyclopentadiene. The dicyclopentadiene or dihydrodicyclopentadiene is hydrogenated, thereby forming tetrahydrodicyclopentadiene. The tetrahydrodicyclopentadiene is isomerized, thereby forming exo-tetrahydrodicyclopentadiene.
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Page/Page column 6
(2021/08/04)
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- Effective synthesis of bicyclodienes via palladium-catalyzed asymmetric allylic alkylation and ruthenium-catalyzed cycloisomerization
-
[n.3.0]Bicycles (n = 3-6) can be synthesized using palladium-catalyzed asymmetric allylic alkylation followed by rutheniumcatalyzedcycloisomerization.Newtypesoftriarylphosphino-1,2-diaminooxazolineligandsshowthesamehighlevelsofenantioselectivity observed with Trost ligand when employed in Pd-catalyzed allylic alkylation reactions. The enyne products of these allylic alkylation reactions were further elaborated using a Ru-catalyzed redox isomerization process, for which a mechanism is proposed.
- Havare, Nizam
-
p. 1445 - 1462
(2021/01/05)
-
- Pd-catalyzed regioselective C?H alkenylation and alkynylation of allylic alcohols with the assistance of a bidentate phenanthroline auxiliary
-
A Pd-catalyzed regioselective C?H alkenylation of allylic alcohols with electron-deficient alkenes has been developed. The key to success is the introduction of bidentately coordinating phenanthroline directing group, which enables the otherwise challenging and regioselective C?H activation at the proximal alkenyl C?H bonds over the conceivably competitive allylic C?O bond activation. The same Pd/phenanthroline system is efficient for the C?H alkynylation of allylic alcohols with alkynyl bromides.
- Hirano, Koji,Miura, Masahiro,Xu, Shibo
-
supporting information
p. 9059 - 9064
(2020/12/02)
-
- Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols
-
Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely, bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton transfer/electron transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.
- Ye, Ke-Yin,Mccallum, Terry,Lin, Song
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supporting information
(2019/06/24)
-
- Cyclotriol derivative and production method and application thereof
-
The invention discloses a cyclotriol derivative and a production method and application thereof. The cyclotriol derivative is of a structure as shown in a general formula I, wherein R1, R2 and R3 areOH or AcNH; R1=OH, and R2=R3=AcNH or R2=OH, and R1=R3=AcNH or R3=OH, and R1=R2=AcNH; * stands for R configuration or S configuration; and Ac stands for caffeoyl CAc or derivatives caffesulfonyl SAc and caffe(mono-methyl ester)phosphonyl PAc of the caffeoyl CAc. According to the production method of the cyclotriol derivative, conditions are mild, automatic and industrial production are easy to achieve, operation is simple, convenient and safe, and the obtained cyclotriol derivative can act on anti-respiratory syncytial virus F protein, has high anti-RSV activity, low cell toxicity and high stability, can be used for producing medicines for treating virus infection, and is especially used for producing medicines for treating respiratory syncytial virus infection.
- -
-
Paragraph 0138; 0146-0148
(2019/09/13)
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- HFIP Solvent Enables Alcohols to Act as Alkylating Agents in Stereoselective Heterocyclization
-
A new method for the stereoselective synthesis of highly functionalized oxygen heterocycles using allyl or benzyl alcohols as alkylating agents is presented. The process is efficient and atom economic, generating water as the only stoichiometric byproduct. Substoichiometric amounts of Ti(OiPr)4 in HFIP solvent are key to this reactivity, and the method tolerates a broad substitution pattern on both the alcohol initiator and homoallylic alcohol substrate. Preliminary mechanistic studies reveal in situ formation of a titanium complex with HFIP which may initiate the cyclization reaction. Further stereoselective functionalization of the products allows access to a diverse range of interesting heterocyclic structures.
- Zhu, Yuxiang,Colomer, Ignacio,Thompson, Amber L.,Donohoe, Timothy J.
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supporting information
p. 6489 - 6493
(2019/05/06)
-
- Chemoselective Luche-Type Reduction of α,β-Unsaturated Ketones by Magnesium Catalysis
-
The chemoselective reduction of α,β-unsaturated ketones by use of an economic and readily available Mg catalyst has been developed. Excellent yields for a wide range of ketones have been achieved under mild reaction conditions, short times, and low catalyst loadings (0.2-0.5 mol %).
- Jang, Yoon Kyung,Magre, Marc,Rueping, Magnus
-
p. 8349 - 8352
(2019/10/16)
-
- Raceme (4AS,7S,7AS)-tert-butyl-7-hydroxyhexahydrocyclopentadiene[B][1,4]oxazine-4(4AH)-formate preparation method
-
A purpose of the present invention is to develop a raceme (4AS,7S,7AS)-tert-butyl-7-hydroxyhexahydrocyclopentadiene[B][1,4]oxazine-4(4AH)-formate preparation method so as to mainly solve the technicalproblem that no synthesis method exists in the prior art. According to the present invention, the method comprises seven steps, and the reaction formula is defined in the specification; and the prepared compound can be used as the useful intermediate or product for synthesizing a plurality of medicines.
- -
-
Paragraph 0006
(2019/12/25)
-
- Discovery of Novel 1-Cyclopentenyl-3-phenylureas as Selective, Brain Penetrant, and Orally Bioavailable CXCR2 Antagonists
-
CXCR2 has emerged as a therapeutic target for not only peripheral inflammatory diseases but also neurological abnormalities in the central nervous system (CNS). Herein, we describe the discovery of a novel 1-cyclopentenyl-3-phenylurea series as potent and CNS penetrant CXCR2 antagonists. Extensive SAR studies, wherein molecules' property forecast index (PFI) was carefully optimized for overall balanced developability profiles, led to the discovery of the advanced lead compound 68 with a desirable PFI. Compound 68 demonstrated good in vitro pharmacology with excellent selectivity over CXCR1 and other chemokine receptors. Rat and dog pharmacokinetics (PK) revealed good oral bioavailability, high oral exposure, and desirable elimination half-life of the compound in both species. In addition, the compound demonstrated dose-dependent efficacy in the in vivo pharmacology neutrophil infiltration "air pouch" model in rodents after oral administration. Further, compound 68 is a CNS penetrant molecule with high unbound fraction in brain tissue.
- Lu, Hongfu,Yang, Ting,Xu, Zhongmiao,Lin, Xichen,Ding, Qian,Zhang, Yueting,Cai, Xin,Dong, Kelly,Gong, Sophie,Zhang, Wei,Patel, Metul,Copley, Royston C. B.,Xiang, Jianing,Guan, Xiaoming,Wren, Paul,Ren, Feng
-
supporting information
p. 2518 - 2532
(2018/03/26)
-
- Microwave-assisted isomerizations of epoxides to allylic alcohols
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The present work reports a study on the isomerization reactions of several alkyl epoxides to the corresponding allylic alcohols or bicyclic alcohols under microwave irradiation. The reaction occurred in the presence of lithium diisopropylamide as a base and different experimental conditions in terms of solvent, amount of the base, times and temperatures. The traditional heating with an oil-bath and the use of alternative organometallic bases, as the Lochmann-Schlosser bases, have been furthermore compared with the microwave heating. The results obtained show that the use of microwave irradiations on promoting the isomerization of epoxides gives access to a series of synthetically useful products, among which allylic alcohols and bicyclic alcohols, depending on the starting substrate.
- Consiglio, Gabriella Barozzino,Mordini, Alessandro
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p. 447 - 454
(2018/05/22)
-
- The hydrogen bond directing effect in nitrile oxide cycloadditions to allylic substituted cyclopentenes
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A quantitative evaluation of the H-bond directing effect on the stereoselectivity in the cycloaddition of nitrile oxides to 2-cyclopenten-1-ol and allylic cyclopentenyl amides is reported. In apolar solvents the H-bond directing effect promotes a high syn stereoselectivity while H-bond acceptor solvents divert the reactions to the anti face of the dipolarophile. Taft's β parameter gives a good description of the solvent effect on the H-bond directing effect. The persistence of some syn stereoselectivity even in good H-bond acceptor solvents points out the existence of some residual hydrogen bond direction. The syn stereoselectivity in the presence of M(II) salts was also investigated and the results discussed in the light of the potential application of these scaffolds in nucleoside synthesis.
- Cardarelli, Anna Maria,Fassardi, Vera,Memeo, Misal Giuseppe,Quadrelli, Paolo
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p. 2602 - 2613
(2017/04/10)
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- COMPOUNDS AND COMPOSITIONS USEFUL FOR TREATING DISORDERS RELATED TO NTRK
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This invention relates to inhibitors of NTRK that are active against wild-type NTRK and its resistant mutants.
- -
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Page/Page column 53; 54
(2017/03/14)
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- The human carbonic anhydrase isoenzymes I and II inhibitory effects of some hydroperoxides, alcohols, and acetates
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The carbonic anhydrases (CAs, EC 4.2.1.1) represent a superfamily of widespread enzymes, which catalyze a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. In this study, a series of hydroperoxides, alcohols, and acetates were tested for the inhibition of the cytosolic hCA I and II isoenzymes. These compounds inhibited both hCA isozymes in the low nanomolar ranges. These compounds were good hCA I inhibitors (Ki s in the range of 24.93–97.99 nM) and hCA II inhibitors (Ki s in the range of 26.04–68.56 nM) compared to acetazolamide as CA inhibitor (Ki : 34.50 nM for hCA I and Ki : 28.93 nM for hCA II).
- Kose, Leyla Polat,Gulcin, ?lhami,Y?ld?r?m, Alper,Atmaca, Ufuk,?elik, Murat,Alwasel, Saleh H.,Supuran, Claudiu T.
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p. 1248 - 1253
(2016/10/09)
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- Total Synthesis of Δ12-Prostaglandin J3: Evolution of Synthetic Strategies to a Streamlined Process
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The total synthesis of Δ12-prostaglandin J3(Δ12-PGJ3, 1), a reported leukemia stem cell ablator, through a number of strategies and tactics is described. The signature cross-conjugated dienone structural motif of 1 was forged by an aldol reaction/dehydration sequence from key building blocks enone 13 and aldehyde 14, whose lone stereocenters were generated by an asymmetric Tsuji–Trost reaction and an asymmetric Mukaiyama aldol reaction, respectively. During this program, a substituent-governed regioselectivity pattern for the Rh-catalyzed C?H functionalization of cyclopentenes and related olefins was discovered. The evolution of the synthesis of 1 from the original strategy to the final streamlined process proceeded through improvements in the construction of both fragments 13 and 14, exploration of the chemistry of the hitherto underutilized chiral lactone synthon 57, and a diastereoselective alkylation of a cyclopentenone intermediate. The described chemistry sets the stage for large-scale production of Δ12-PGJ3and designed analogues for further biological and pharmacological studies.
- Nicolaou,Pulukuri, Kiran Kumar,Yu, Ruocheng,Rigol, Stephan,Heretsch, Philipp,Grove, Charles I.,Hale, Christopher R. H.,ElMarrouni, Abdelatif
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supporting information
p. 8559 - 8570
(2016/07/11)
-
- Bismuth-substituted "sandwich" type polyoxometalate catalyst for activation of peroxide: Umpolung of the peroxo intermediate and change of chemoselectivity
-
The epoxidation of alkenes with peroxides by WVI, MoVI, VV, and TiIV compounds is well established, and it is well accepted that the active intermediate peroxo species are electrophilic toward nucleophilic substrates. Polyoxotungstates, for example, those of the "sandwich" structure, [WZn(TM-L)2(ZnW9O34)2]q- in which TM = transition metal and L = H2O, have in the past been found to be excellent epoxidation catalysts. It has now been found that substituting the Lewis basic BiIII into the terminal position of the "sandwich" polyoxometalate structure to yield [Zn2BiIII2(ZnW9O34)2]14- leads to an apparent umpolung of the peroxo species and formation of a nucleophilic peroxo intermediate. There are two lines of evidence that support the formation of a reactive nucleophilic peroxo intermediate: (1) More electrophilic sulfoxides are more reactive than more nucleophilic sulfides, and (2) nonfunctionalized aliphatic alkenes and dienes showed ene type reactivity rather than epoxidation pointing toward "dark" formation of singlet oxygen from the nucleophilic intermediate peroxo species. Allylic alcohols reacted much faster than alkenes but showed chemoselectivity toward C-H bond activation of the alcohol and formation of aldehydes or ketones rather than epoxidation. This explained via alkoxide formation at the BiIII center followed by oxidative β-elimination.
- Amanchi, Srinivasa Rao,Khenkin, Alexander M.,Diskin-Posner, Yael,Neumann, Ronny
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p. 3336 - 3341
(2015/06/16)
-
- Eco-friendly stereoselective reduction of α,β-unsaturated carbonyl compounds by Er(OTf)3/NaBH4 in 2-MeTHF
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An operationally simple and environmentally benign catalytic procedure has been developed to selectively reduce different α,β-unsaturated ketones. The corresponding allylic alcohols are obtained with high chemo- and diastereoselectivity using Er(OTf)3 and NaBH4 in 2-MeTHF. This protocol reduces the amount of catalyst and NaBH4 needed, compared to classical procedures and the stages of extraction/purification are carried out in aqueous solutions avoiding the use of toxic solvents. Taking into account that Er(OTf)3 can be considered even less toxic than table salt and the 'greenness' of 2-MeTHF as a solvent, the system Er(OTf)3/2-MeTHF can be proposed as a cheap, efficient, and environmentally sustainable reduction system for the synthesis of allylic alcohols.
- Nardi, Monica,Sindona, Giovanni,Costanzo, Paola,Oliverio, Manuela,Procopio, Antonio
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p. 1132 - 1135
(2015/02/19)
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- SYNTHESIS OF DELTA 12-PGJ3 AND RELATED COMPOUNDS
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In one aspect, the present invention provides novel derivatives of Δ12-PGJ3 and modular synthetic pathways to obtaining Δ12-PGJ3 and derivatives thereof. In some aspects, the present derivatives of Δ12-PGJ3 are useful as chemotherapeutic agents. The present disclosure also describes compositions of these derivatives as well as methods of use of the derivatives thereof.
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Page/Page column 92
(2015/04/15)
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- Calcium-catalyzed carboarylation of alkynes
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The first transition-metal-free carboarylation of alkynes with commercial and readily available alcohols as alkylating agents was realized in the presence of an environmentally benign calcium catalyst. Thereby, a novel protocol for the one-step synthesis of highly congested, all-carbon tetrasubstituted alkenes, as incorporated in potentially bioactive, complex dihydronaphthalene, chromene and dihydroquinoline structures, is provided. The reaction features an unprecedented, particularly wide substrate scope, good functional-group tolerance and simple experimental operation under mild reaction conditions. Finally free: The first transition-metal-free one-step synthesis of highly congested, all-carbon tetrasubstituted olefins has been realized by a calcium-catalyzed carboarylation reaction. Internal alkynes react with alcohols as alkylating reagent under mild reaction conditions, which provides access to a variety of useful structural scaffolds via highly reactive trisubstituted vinyl cations.
- Fu, Liang,Niggemann, Meike
-
supporting information
p. 6367 - 6370
(2015/04/22)
-
- Multiple Olefin Metathesis Polymerization That Combines All Three Olefin Metathesis Transformations: Ring-Opening, Ring-Closing, and Cross Metathesis
-
We demonstrated tandem ring-opening/ring-closing metathesis (RO/RCM) polymerization of monomers containing two cyclopentene moieties and postmodification via insertion polymerization. In this system, well-defined polymers were efficiently formed by tandem cascade RO/RCM reaction pathway. Furthermore, these polymers could be transformed to new A,B-alternating copolymers via a sequential cross metathesis reaction with a diacrylate. Additionally, we demonstrated the concept of multiple olefin metathesis polymerization in which the dicyclopentene and diacrylate monomers underwent all three olefin metathesis transformations (ring-opening, ring-closing, and cross metathesis) in one shot to produce A,B-alternating copolymer.
- Lee, Ho-Keun,Bang, Ki-Taek,Hess, Andreas,Grubbs, Robert H.,Choi, Tae-Lim
-
supporting information
p. 9262 - 9265
(2015/08/11)
-
- 1 -(CYCLOPENT-2-EN-1 -YL)-3-(2-HYDROXY-3-(ARYLSULFONYL)PHENYL)UREA DERIVATIVES AS CXCR2 INHIBITORS
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The invention relates to 1-(3-sulfonylphenyl)-3-(cyclopent-2-en-1-yl)urea derivatives, and their use in treating or preventing diseases and conditions mediated by the CXCR2 receptor. In addition, the invention relates to compositions containing the derivatives and processes for their preparation.
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Page/Page column 43
(2015/12/18)
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- Hydrogen-transfer catalysis with Cp*IrIII complexes: The influence of the ancillary ligands
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Fourteen Cp*IrIII complexes, bearing various combinations of N- and C-spectator ligands, are assayed in hydrogen-transfer catalysis from isopropyl alcohol to acetophenone under various conditions to investigate ligand effects in this widely used reaction. The new cationic complexes bearing monodentate pyridine and N-heterocyclic carbene (NHC) ligands were characterized crystallographically and by variable-temperature nuclear magnetic resonance (VT-NMR). Control experiments and mercury poisoning tests showed that iridium(0) nanoparticles, although active in the reaction, are not responsible for the high activity observed for the most active precatalyst [Cp*Ir(IMe) 2Cl]BF4 (6). For efficient catalysis, it was found necessary to have both NHCs in monodentate form; tying them together in a bis-NHC chelate ligand gave greatly reduced activity. The kinetics of the base-assisted reaction showed induction periods as well as deactivation processes, and H/D scrambling experiments cast some doubt on the classical monohydride mechanism.
- Hintermair, Ulrich,Campos, Jesus,Brewster, Timothy P.,Pratt, Lucas M.,Schley, Nathan D.,Crabtree, Robert H.
-
-
- Heterogeneous platinum catalytic aerobic oxidation of cyclopentane-1,2- diols to cyclopentane-1,2-diones
-
A method for the aerobic oxidation of cyclopentane-1,2-diols to the corresponding diketones over a commercial heterogeneous Pt/C catalyst is described. Unsubstituted and 3- or 4-substituted cyclopentane-1,2-diols are oxidized to 1,2-dicarbonyl compounds in good yields under the reported optimized reaction conditions (atmospheric air, 1 mol % of catalyst, 1 equiv of LiOH, aqueous solvents and 60 °C temperature). The method is applicable for producing cyclopentane-1,2-diketones in a scalable manner.
- Reile, Indrek,Kalle, Sigrid,Werner, Franz,J?rving, Ivar,Kudrjashova, Marina,Paju, Anne,Lopp, Margus
-
supporting information
p. 3608 - 3613
(2014/05/20)
-
- Synthesis and biological activity of Citridone A and its derivatives
-
Citridone A (1), originally isolated as a potentiator of antifungal miconazole activity from a fungal culture broth, has a phenyl-R-furopyridone structure. Because of its unique ring structure, 11 derivatives were chemically synthesized and their biological activity was evaluated. Derivatives 17, 20 and 21 potentiated miconazole activity against Candida albicans. Furthermore, 1, 14, 20 and 21 were found to inhibit yellow pigment production in methicillin-resistant Staphylococcus aureus.
- Fukuda, Takashi,Shimoyama, Kenta,Nagamitsu, Tohru,Tomoda, Hiroshi
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p. 445 - 450
(2014/07/08)
-
- Electrochemical intramolecular aminooxygenation of unactivated alkenes
-
An electrochemical approach to the intramolecular aminooxygenation of unactivated alkenes has been developed. This process is based on the addition of nitrogen-centered radicals, generated through electrochemical oxidation, to alkenes followed by trapping of the cyclized radical intermediate with 2,2,6,6-tetramethylpiperidine-N-oxyl radical (TEMPO). Difunctionalization of a variety of alkenes with easily available carbamates/amides and TEMPO affords aminooxygenation products in high yields and with excellent trans selectivity for cyclic systems (d.r. up to>20:1). The approach provides a much-needed complementary route to existing cis-selective methods.
- Xu, Fan,Zhu, Lin,Zhu, Shaobin,Yan, Xiaomei,Xu, Hai-Chao
-
supporting information
p. 12740 - 12744
(2015/03/30)
-
- Precision vinyl acetate/ethylene (VAE) copolymers by ROMP of acetoxy-substituted cyclic alkenes
-
Precision linear vinyl acetate/ethylene (VAE) copolymers containing acetoxy groups on precisely every eighth backbone carbon were synthesized by ring-opening metathesis polymerization (ROMP) of racemic 3-acetoxy cyclooctene (3AcCOE) followed by hydrogenation. The use of enantiomerically pure 3AcCOE resulted in an optically active polyalkenamer that afforded isotactic precision VAE materials after hydrogenation. Both of these VAE polymers are semicrystalline (by differential scanning calorimetry and wide-angle X-ray scattering) due to their high degrees of regioregularity and the isotactic VAE samples exhibited a higher apparent degree of crystallinity and melting point compared to the atactic version. In contrast, analogous linear VAE copolymers derived from ROMP-hydrogenation of racemic 4- or 5-acetoxy cyclooctenes were regio-irregular and completely amorphous. The ROMP-hydrogenation of 3-acetoxy cycloheptene also affords precision linear VAE copolymers with acetoxy groups on every seventh carbon, but this polymer was noncrystalline. Mechanical characterization showed that the precision 3AcCOE-derived VAE samples possess improved mechanical properties compared to the compositionally similar commercial VAE copolymers produced by radical copolymerization.
- Zhang, Jihua,Matta, Megan E.,Martinez, Henry,Hillmyer, Marc A.
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p. 2535 - 2543
(2013/06/04)
-
- Mesoporous carbon nitride synthesized by nanocasting with urea/formaldehyde and metal-free catalytic oxidation of cyclic olefins
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Mesostructured carbon nitride has been synthesized by nanocasting method with urea/formaldehyde as carbon and nitrogen sources by using disk-shaped 2D hexagonal mesoporous silica (INC-2) as a hard template. The resulted mesoporous carbon nitride (UF-MCN) was characterized as a graphitic structure with hexagonal pores of 3-4 nm and short channels in the submicron range. The catalytic oxidation ability of UF-MCN was demonstrated in the metal-free oxidation of cyclic olefins with hydrogen peroxide. The conversions for cyclopentene, cyclohexene and cis-cyclooctene were obtained in the range of 65-80% and selectivities onto epoxides were 40-90%, respectively. The UF-MCN could illustrate the considerable catalytic oxidation activities due to the existence of surface oxygen species.
- Min, Byung-Hoon,Ansari, Mohd Bismillah,Mo, Yong-Hwan,Park, Sang-Eon
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p. 156 - 163
(2013/08/24)
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- L-Proline-derived ligands to mimic the '2-His-1-carboxylate' triad of the non-haem iron oxidase active site
-
Non-haem iron(II) oxidases (NHIOs) catalyse a variety of oxidative transformations in biology. The iron-binding environment of the NHIO active site typically incorporates a '2-His-1-carboxylate' facial triad of amino acid side-chains, a motif that has emerged as a defining feature of the enzyme family. Towards the goal of biomimetic, iron-mediated C-H activation we have synthesized a series of peptidomimetic ligands from l-proline. By coupling l-proline to 2,6-bis(bromomethyl)pyridine, 2-(bromomethyl)-6-((tert- butyldimethylsilyloxy)methyl)pyridine and picolinic acid, we have generated several new ligand architectures designed to complex with iron(II) and mimic the NHIO active site. The resulting iron complexes promote modest levels of alkene dihydroxylation and allylic oxidation using hydrogen peroxide as oxidant.
- Dungan, Victoria J.,Wong, Shwo Mun,Barry, Sarah M.,Rutledge, Peter J.
-
experimental part
p. 3231 - 3236
(2012/06/01)
-
- Aerobic oxidation of cycloalkenes catalyzed by iron metal organic framework containing N-hydroxyphthalimide
-
Iron metal organic framework [Fe(BTC)] loaded with N-hydroxyphthalimide (NHPI) promotes the aerobic oxidation of (cyclo)alkenes to give variable percentages of allylic oxidation products and the corresponding epoxide, dependidng on the nature of the substrate. In the case of cyclopentene and cyclohexene, aerobic oxidation catalyzed by NHPI/Fe(BTC) renders their corresponding unsaturated cyclic alcohol and ketone with 97% selectivity in 5 h at 6% and 12% conversion, respectively. Under the same experimental conditions, cyclooctene exhibited 95% selectivity toward the formation of cyclooctene oxide with 2% of cyclooctenol/one at 4 h. Cycloheptene as susbstrate exhibits an intermediate behavior, and the aerobic oxidation catalyzed by NHPI/Fe(BTC) leads to the formation of cycloheptenol/cycloheptenone with 77% selectivity, accompanied by 23% of cycloheptene oxide at 4 h. Further experiments with non-symmetric olefins exhibited also a mixture of products including epoxides and allyic products. A mechanism to explain these experimental results has been proposed.
- Dhakshinamoorthy, Amarajothi,Alvaro, Mercedes,Garcia, Hermenegildo
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experimental part
p. 259 - 265
(2012/06/01)
-
- Lanthanide replacement in organic synthesis: Luche-type reduction of α,β-unsaturated ketones in the presence of calcium triflate
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Development of a calcium-mediated regioselective 1,2-reduction of challenging α,β-unsaturated ketones, such as 2-cyclopententone, is reported. The corresponding allylic alcohols are obtained in very good regioselectivities using Ca(OTf)2 and NaBH4. Furthermore, we have shown that our method can stereoselectively reduce aziridinyl ketones.
- Forkel, Nina V.,Henderson, David A.,Fuchter, Matthew J.
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supporting information; experimental part
p. 2129 - 2132
(2012/09/08)
-
- CO2 activation and promotional effect in the oxidation of cyclic olefins over mesoporous carbon nitrides
-
Mesoporous carbon nitrides (MCN) were prepared by a nano-casting method using mesoporous silica as a template with different carbon and nitrogen sources like melamine only (MS-MCN), urea-formaldehyde (UF-MCN) and melamine-glyoxal (MG-MCN). These mesoporous carbon nitride materials possess nitrogen moieties which behave like a CO2-philic surface facilitating oxidation of cyclic olefins by molecular oxygen in the co-presence of CO2 below supercritical conditions. The co-presence of CO2 augmented the conversions of cyclic olefins at low pressures of CO2, depicting a promotional effect. Approaches towards quantification of promotional effects and insights into the promotional aspects have been studied.
- Ansari, Mohd Bismillah,Min, Byung-Hoon,Mo, Yong-Hwan,Park, Sang-Eon
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experimental part
p. 1416 - 1421
(2011/08/03)
-
- Palladium-catalyzed and samarium-promoted coupling of stereochemically-biased allylic acetates with carbonyl compounds
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Stereochemically-biased bicyclic allylic acetates endo- and exo-1 were shown as being allyl donors for Pd-catalyzed carbonyl allylation using stoichiometric quantities of samarium diodide. Cyclopentenyl acetate and bicyclic derivatives 1 react with cyclic ketones in the presence of SmI2 without requirement of palladium catalysis. Use of enantiomerically enriched substrate suggests that the reaction goes through a π-allyl samarium complex. However, this reactivity appears to be restricted to strained cyclopentenyl acetates since other linear and cyclic allylic acetates do not give the carbonyl allylation product.
- Jacquet, Olivier,Bergholz, Timm,Magnier-Bouvier, Caroline,Mellah, Mohamed,Guillot, Régis,Fiaud, Jean-Claude
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experimental part
p. 222 - 226
(2010/03/01)
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- Stereoselective aziridination of cyclic allylic alcohols using chloramine-T
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The stereoselective aziridination of a range of cyclic allylic alcohols using two different chloramine salts (4-MeC6H4SO 2NClNa, TsNClNa and t-BuSO2NClNa, BusNClNa) has been explored. The stereoselectivity of these reactions was highly dependent on the structure of the allylic alcohol and the chloramine salt. Generally, mixtures of cis- and trans-hydroxy aziridines were obtained, in which the major diastereomer was the cis-hydroxy aziridine, whilst complete cis- diastereoselectivity was observed in the aziridination of 1,3-disubstituted allylic alcohols. In each case studied, aziridination using BusNClNa gave higher cis-stereoselectivity than that observed for the same reaction using TsNClNa. Unexpectedly, application of the aziridination conditions to 1-substituted cyclopen-2-en-1-ols did not generate the aziridines. Instead, epoxy sulfonamides were obtained.
- Coote, Susannah C.,O'Brien, Peter,Whitwood, Adrian C.
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supporting information; experimental part
p. 4299 - 4314
(2009/02/07)
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- Hydroxyl-directed nitrile oxide cycloaddition reactions with cyclic allylic alcohols
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Diastereoselective cycloaddition reactions between a nitrile oxide and cyclic allylic alcohols are reported. The products isolated are densely functionalized building blocks that are not otherwise easily accessed with existing methods and concepts previously established for the construction of acyclic polyketides.
- Becker, Nina,Carreira, Erick M.
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p. 3857 - 3858
(2008/02/12)
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- Chemoselective hydrogenation of α,β-unsaturated ketones to allylic alcohols, catalyzed by a mononuclear ruthenium complex containing trans PnBu3 and PPh3 ligands
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The ruthenium(II) bis(acetate) complex Ru(CO)2(OAc)2(PnBu3) (PPh3) (OAc = acetate) containing two different trans phosphine ligands, has been employed as pre-catalyst for the chemoselective hydrogenation of α,β-unsaturated ketones to allylic alcohols. Analogous catalytic reactions with the homodiphosphine pre-catalysts Ru(CO)2(OAc)2(PnBu3) 2 and Ru(CO)2(OAc)2(PPh3)2 gave lower conversions and selectivities. Batch catalytic reactions and operando high-pressure NMR experiments have contributed to establish that the hydrogenation of the C{double bond, long}O group is performed by the heterodiphosphine monohydride RuH(CO)2(OAc)(PnBu3)(PPh3) generated in situ by hydrogenation of the bis(OAc) precursor. PPh3 unfastening from this monohydride complex is an essential condition for the occurrence of catalytic activity.
- Micoli, Francesca,Oberhauser, Werner,Salvini, Antonella,Bianchini, Claudio
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p. 2334 - 2341
(2008/01/27)
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- Liquid-phase epoxidation of alkenes using molecular oxygen catalyzed by vanadium cation-exchanged montmorillonite
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Vanadium cation-exchanged montmorillonite can efficiently catalyze the selective epoxidation of various alkenes and the oxygenation of adamantane using molecular oxygen as a sole oxidant. Copyright
- Mitsudome, Takato,Nosaka, Naoya,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 1626 - 1627
(2007/10/03)
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- Anti-ischemic compounds
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The present invention is related to a compound of formula (I), salts and pro-drugs of the compound (I) and methods for treating and/or preventing partial or total ischemia, methods for treating and/or preventing pathologies associated with ischemia or with mitochondrial deficiencies.
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- An approach to the tricyclic lactone core of brasoside and related natural products
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A one-pot iodine atom transfer/cyclisation and intermolecular olefination is described for the efficient, stereoselective construction of bicyclic lactone intermediates en route to compound 21, a potential precursor to the brasoside (1) skeleton.
- Robertson, Jeremy,Ménard, Morgan,Ford, Rhonan
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p. 2788 - 2790
(2007/10/03)
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- Reductive alkylation of β-alkoxy aziridines: New route to substituted allylic amines
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(Chemical Equation Presented) A new route to substituted cyclic allylic amines via the reductive alkylation of β-alkoxy aziridines using excess alkyllithium reagents is described.
- Rosser, Clare M.,Coole, Susannah C.,Kirby, Jonathan P.,O'Brien, Peter,Caine, Darren
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p. 4817 - 4819
(2007/10/03)
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- Selective reductive cleavage of 2,3-epoxybromides by the InCl 3-NaBH4 reagent system
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A combination of sodium borohydride and a catalytic amount of indium(III) chloride in acetonitrile reduces 2,3-epoxybromides to the corresponding allylic alcohols in good yields involving reduction of the bromo moiety followed by selective C-O bond cleavage through a radical process. Several aromatic, cyclic and open-chain bromoepoxides successfully participated in this reaction.
- Ranu, Brindaban C.,Banerjee, Subhash,Das, Arijit
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p. 8579 - 8581
(2007/10/03)
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- Acyl and sulfonyl derivatives of 6,9-disubstituted 2-(trans-1,4-diaminocyclohexyl)-purines and their use as antiproliferative agents
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The present invention is directed to acyl and sulfonyl derivatives of 6,9-disubstituted 2-(trans-1,4-diaminocyclohexyl)-purines and methods of using the same as antiproliferative agents or to prevent apoptosis.
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- Highly active delaminated Ti-MWW for epoxidation of bulky cycloalkenes with hydrogen peroxide
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A novel titanosilicate, prepared by the partial delamination of acid-treated Ti-MWW, possesses an extremely high specific surface area and proves to be a selective and active liquid-phase oxidation catalyst for bulky alkenes.
- Nuntasri, Duangamol,Wu, Peng,Tatsumi, Takashi
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p. 326 - 327
(2007/10/03)
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- Equilibrium constants for dehydration of water adducts of aromatic carbon-carbon double bonds
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Equilibrium constants (Kde) are reported for the dehydration of hydrates of benzene, naphthalene, phenanthrene, and anthracene. Free energies of formation of the hydrates (ΔG°f(aq)) are derived by combining free energies of formation of the parent (dihydroaromatic) hydrocarbon with estimates of the increment in free energy (ΔGOH) accompanying replacement of a hydrogen atom of the hydrocarbon by a hydroxyl group. Combining these in turn with free energies of formation of H2O and of the aromatic hydrocarbon products furnishes the desired equilibrium constants, The method depends on the availability of thermodynamic data (i) for the hydrocarbons from which the hydrates are derived by hydroxyl substitution and (ii) for a sufficient range of alcohols to assess the structural dependence of ΔGOH. The data comprise chiefly heats of formation and standard entropies in the gas phase and free energies of transfer from the gas phase to aqueous solution (the latter being derived from vapor pressures and solubilities). They also include experimental measurements of equilibrium constants for dehydration of alcohols, especially cyclic, allylic, and benzylic alcohols. In general ΔGOH depends on whether the alcohol is (a) primary, secondary, or tertiary; (b) allylic or benzylic; and (c) open chain or cyclic. Differences in geminal interactions of the hydroxyl group of the alcohol with α-alkyl and vinyl or phenyl groups account for variations in ΔGOH of 5 kcal mol-1. Weaker variations which arise from β-vinyl/OH or β-phenyl/OH interactions present in the aromatic hydrates but not in experimentally studied analogues are estimated as 1.0 kcal mol-1. Equilibrium constants for dehydration may be expressed as their negative logs (pKde). Reactions yielding the following aliphatic, aromatic, and antiaromatic unsaturated products then have pKde values: +4.8, ethene; +15.0, ethyne; +22.1, cyclopropene; +28.4 cyclobutadiene; -22.2, benzene; -14.6, naphthalene; -9.2, phenanthrene; -7.4, anthracene. Large positive values are associated with formation of strained or antiaromatic double bonds and large negative values with aromatic double bonds. Trends in pKde parallel those of heats of hydrogenation. The results illustrate the usefulness of a substituent treatment for extending the range of currently available free energies of formation. In addition to hydroxyl substituent effects, ΔGOH, values of ΔGπ for substitution of a π-bond in a hydrocarbon are reported.
- Dey, Joykrishna,O'Donoghue, AnnMarie C.,More O'Ferrall, Rory A.
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p. 8561 - 8574
(2007/10/03)
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- An experimental and computational study of 1,2-hydrogen migrations in 2-hydroxycyclopentylidene and its conjugate base
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Thermal decomposition of α-hydroxydiazirine 2 gives primarily cyclopentanone and some allylic alcohol, in similar amounts as the known cyclohexyl analogue 1. Calculations (B3LYP/6-31+G*) also show cyclopentanone to be the major product of this carbene rearrangement. Diazirine 2 and the lithium salt of the corresponding conjugate base 3 were decomposed by photolysis. The proportion of ketone formed increases with deprotonation, a trend also found computationally. In comparison, the base-induced isomerization of cyclopentene oxide, which proceeds via α-elimination to a carbenoid intermediate similar to that obtained from 3, yields primarily allylic alcohol rather than ketone; neither ring size nor charge thus accounts for the unusual product distribution observed. Interestingly, the calculations reveal that in the gas phase with no counterion, the singlet, oxyanionic carbene, and the α-deprotonated epoxide are the same, rather than discrete structures. This intramolecular complexation stablilizes the oxyanionic carbene by 20-25 kcal/mol.
- Morgan,O'Connor,Humphrey,Buschman
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p. 1600 - 1606
(2007/10/03)
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- Phenylethanolamine compounds useful as beta 3 agonists, process for producing the same, and intermediates in the production of the same
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PCT No. PCT/JP96/03097 Sec. 371 Date Apr. 24, 1998 Sec. 102(e) Date Apr. 24, 1998 PCT Filed Oct. 24, 1996 PCT Pub. No. WO97/15549 PCT Pub. Date May 1, 1997The present invention relates to phenylethanolamine compounds represented by general formula [I]: (where R1 represents hydrogen or halogen; R2 represents hydrogen, hydroxy, lower alkoxy, lower alkoxy substituted with one or two lower alkoxycarbonyl or carboxy groups, lower alkoxy substituted with lower alkylaminocarbonyl which may be substituted with lower alkoxy, lower alkoxy substituted with cyclic aminocarbonyl of 4 to 6 carbon atoms, lower alkoxycarbonyl or carboxy; R3 represents hydrogen, hydroxy, lower alkoxy or lower alkoxy substituted with one or two lower alkoxycarbonyl or carboxy groups; R2 and R3 may be bonded to each other to form methylenedioxy substituted with carboxy or lower alkoxycarbonyl; and m and n are 0 or 1), and their pharmacologically acceptable salts, which have a potent beta 3 adrenergic stimulating effect and high beta 3 adrenergic receptor selectivity, as well as to processes for their production and intermediates in their production.
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- Fluoro alcohol as reaction medium: One-pot synthesis of β-hydroxy sulfoxides from epoxides
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β-Hydroxy sulfoxides were obtained in one-pot synthesis by the ring opening of oxiranes with thiols in hexafluoroisopropanol (HFIP) without any catalyst, followed by in situ oxidation under neutral conditions. The reaction is anti-selective. β-Hydroxy sulfoxides were transformed by pyrolysis in the corresponding allylic alcohols. (C) 2000 Elsevier Science Ltd.
- Kesavan, Venkitasamy,Bonnet-Delpon, Danièle,Bégué, Jean-Pierre
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p. 2895 - 2898
(2007/10/03)
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- Synthesis of C-5'-nor-dideoxycarbanucleosides structurally related to neplanocin C
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Purine carbanucleosides built on a 6-oxabicyclo[3.1.0]hexane template were synthesized from readily available 2-cyclopentenone employing a Mitsunobu reaction to incorporate the base onto the carbocyclic ring. Both adenosine and guanosine analogues exhibited moderate antiviral activity.
- Comin, Maria J.,Pujol, Carlos A.,Damonte, Elsa B.,Rodriguez, Juan B.
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p. 2219 - 2231
(2007/10/03)
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- Some allylic substituent effects in ring-closing metathesis reactions: allylic alcohol activation.
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[formula: see text] Dienes 2a-e were used to study allylic substituent effects in the ring-closing metathesis reaction (RCM). Both the steric and electronic character of the allylic substituents were found to influence alkene reactivities. Free allylic hydroxyl groups exert a large activating effect on the RCM reaction rates.
- Hoye,Zhao
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p. 1123 - 1125
(2008/02/09)
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- Tetrachlorocyclopentadienone O-Oxide, a Facile Oxygen-Atom-Transfer Reagent: The Disproportionation of Cycloalkyldioxyl Radicals
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Photolysis of tetrachlorodiazocyclopentadiene (1) in oxygen-saturated hydrocarbon solvents results in the transient formation of tetrachlorocyclopentadienone O-oxide (3). This rapidly decomposes, giving rise to products derived from oxidation of the hydrocarbons. Cyclopentane, cyclopentene, cycloheptane, cycloheptene, cycloheptatriene, and indene have been studied. Cycloheptatriene and indene gave only low yields of tractable products, but the others gave the corresponding ketones and secondary alcohols as the major products. Although yields varied considerably, the ketone and alcohol products were always obtained, within experimental error, in a 1 : 1 molar ratio. This observed product ratio supports the disproportionation of cycloalkyldioxyl radicals as a crucial step.
- Dunkin, Ian R.,McCluskey, Adam
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p. 1397 - 1400
(2007/10/03)
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