- Total Synthesis of (-)-Nodulisporic Acids D, C, and B: Evolution of a Unified Synthetic Strategy
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A unified synthetic strategy leading to the total synthesis of (-)-nodulisporic acids D, C, and B is described. Key synthetic transformations include a nickel-chromium-mediated cyclization, an aromatic ring functionalization employing a novel copper-promoted alkylation, a palladium-catalyzed cross-coupling cascade/indole ring construction, and a palladium-mediated regio- and diastereoselective allylic substitution/cyclization reaction, the latter to construct ring D.
- Zou, Yike,Li, Xiangqin,Yang, Yun,Berritt, Simon,Melvin, Jason,Gonzales, Stephen,Spafford, Matthew,Smith, Amos B.
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- Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
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Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
- Barman, Milan K.,Das, Kuhali,Maji, Biplab
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p. 1570 - 1579
(2019/01/30)
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- Storing redox equivalent in the phenalenyl backbone towards catalytic multi-electron reduction
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Storing and transferring electrons for multi-electron reduction processes are considered to be the key steps in various important chemical and biological transformations. In this work, we accomplished multi-electron reduction of a carboxylic acid via a hydrosilylation pathway where a redox-active phenalenyl backbone in Co(PLY-O,O)2(THF)2, stores electrons and plays a preponderant role in the entire process. This reduction proceeds by single electron transfer (SET) from the mono-reduced ligand backbone leading to the cleavage of the Si-H bond. Several important intermediates along the catalytic reduction reaction have been isolated and well characterized to prove that the redox equivalent is stored in the form of a C-H bond in the PLY backbone via a ligand dearomatization process. The ligand's extensive participation in storing a hydride equivalent has been conclusively elucidated via a deuterium labelling experiment. This is a rare example where the ligand orchestrates the multielectron reduction process leaving only the metal to maintain the conformational requirements and fine tunes the electronics of the catalyst.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Shaw, Bikash Kumar,Vaidya, Shefali,Pariyar, Anand,Vijaykumar, Gonela,Adhikari, Debashis,Mandal, Swadhin K.
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p. 7433 - 7441
(2019/08/15)
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- Total Synthesis of (-)-Nodulisporic Acid D
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A convergent total synthesis of the architecturally complex indole diterpenoid (-)-nodulisporic acid D has been achieved. Key synthetic transformations include vicinal difunctionalization of an advanced α,β-unsaturated aldehyde to form the E,F-trans-fused 5,6-ring system of the eastern hemisphere and a cascade cross-coupling/indolization protocol leading to the CDE multisubstituted indole core.
- Zou, Yike,Melvin, Jason E.,Gonzales, Stephen S.,Spafford, Matthew J.,Smith, Amos B.
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supporting information
p. 7095 - 7098
(2015/06/25)
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- Discovery of a clinical stage multi-kinase inhibitor sodium (E)-2-{2-methoxy-5-[(2′,4′,6′-trimethoxystyrylsulfonyl)methyl] phenylamino}acetate (ON 01910.Na): Synthesis, structure-activity relationship, and biological activity
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Cyclin D proteins are elevated in many cancer cells, and targeted deletion of cyclin D1 gene in the mammary tissues protects mice from breast cancer. Accordingly, there is an increasing awareness of this novel nonenzymatic target for cancer therapeutics. We have developed novel, nonalkylating styrylbenzylsulfones that induce cell death in wide variety of cancer cells without affecting the proliferation and survival of normal cells. The development of derivatized styrylbenzylsulfones followed logically from a tumor cell cytotoxicity screen performed in our laboratory that did not have an a priori target profile. Modifications of some of the precursor molecules led to lead optimization with regard to tumor cell cytotoxicity. In this report we describe the synthesis and structure-activity relationships of novel, nonalkylating (E)-styrylbenzylsulfones and the development of the novel anticancer agent sodium (E)-2-{2-methoxy-5-[(2′,4′,6′- trimethoxystyrylsulfonyl)methyl]phenylamino}acetate (ON 01910.Na), which is in phase III trials for myelodysplastic syndromes (MDS) associated with aberrant expression of cyclin D proteins.
- Reddy, M. V. Ramana,Venkatapuram, Padmavathi,Mallireddigari, Muralidhar R.,Pallela, Venkat R.,Cosenza, Stephen C.,Robell, Kimberly A.,Akula, Balaiah,Hoffman, Benjamin S.,Reddy, E. Premkumar
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experimental part
p. 6254 - 6276
(2011/11/01)
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- Synthesis and structure-activity relationships of N-aryl(indol-3-yl)glyoxamides as antitumor agents
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The synthesis and study of the structure-activity relationships of cytotoxic compounds based on N-pyridinyl or N-aryl-2-(1-benzylindol-3-yl)glyoxamide skeleton, represented by the lead structures D-24241 and D-24851, are described. The presence of N-(pyridin-4-yl) moiety was crucial for activity and 2-[1-(4-chloro-3-nitrobenzyl)-1H-indol-3-yl]-2-oxo-N-(pyridin-4-yl)aceta mide (55), the most potent derivative, showed IC50 = 39 nM, 51 nM and 11 nM against HeLa/KB (human cervix carcinoma), L1210 (murine leukemia) and SKOV3 (human ovarian carcinoma) cell lines proliferation assay, respectively, as active as the lead compounds.
- Marchand, Pascal,Antoine, Maud,Baut, Guillaume Le,Czech, Michael,Baasner, Silke,Guenther, Eckhard
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experimental part
p. 6715 - 6727
(2009/12/06)
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- NOVEL SULFONAMIDE COMPOUNDS
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The invention relates to novel sulfonamide compounds and their use as orexin receptor antagonists.
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Page/Page column 10
(2009/12/02)
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- NOVEL SULFONAMIDE COMPOUNDS
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The invention relates to sulfonamide compounds of formula (I), where A, B, R3 and R4 are as defined in the claims, and their use as orexin receptor antagonists in the prevention and treatment of eating and drinking disorders, all types of sleep disorders, all kinds of cognitive dysfunctions in the healthy population and psychiatric and neurologic disorders. Formula (I).
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Page/Page column 24
(2008/06/13)
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- Aniline derivatives possessing an inhibitory effect of nitric oxide synthase
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Compounds represented by the general formula (1): ? (where R1is SR6or NR7R8, where R6is typically an alkyl group having 1-6 carbon atoms, R7is a hydrogen atom, an alkyl group having 1-6 carbon atoms or a nitro group, and R8is a hydrogen atom or an alkyl group having 1-6 carbon atoms; R2and R3are each typically a hydrogen atom or an alkyl group having 1-6 carbon atoms; R4is a hydrogen atom, an alkyl group having 1-6 carbon atoms or an amidino group of which the amine portion may be substituted by an alkyl or nitro group; R5is a hydrogen atom or an alkyl group having 1-6 carbon atoms; Y1, Y2, Y3and Y4which may be the same or different are each typically a hydrogen atom, a halogen atom or an alkoxy group having 1-6 carbon atoms; n and m are each an integer of 0 or 1), or possible stereoisomers or optically active forms of the compounds or pharmaceutically acceptable salts thereof. The compounds possess a potent nitric oxide synthase inhibiting activity and are useful as therapeutics of cerebrovascular diseases.
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- Hydroxybenzotriazole supporte sur polymere: mise au point sur la synthese du PHBT
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Due to some difficulties encountered in order to obtain a polystyrene supported hydroxybenzotriazole (PHBT) as described by Patchornik, a reexamination of its synthesis and reactivity in peptide chemistry was undertaken.Experimental conditions will be discussed, particularly the synthesis of the starting 4-chloro-3-nitro benzylic alcohol and the influence of the polymer loading.
- Berrada, Amal,Cavelier, Florine,Jacquier, Robert,Verducci, Jean
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p. 511 - 514
(2007/10/02)
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- USE OF POLYMERIC ACTIVATED ESTERS BASED ON 1-HYDROXYBENZOTRIAZOLE IN PEPTIDE SYNTHESIS
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A further study was made of the possibility of using polymeric activated esters based on 1-hydroxybenzotriazole in the peptide synthesis as illustrated by the synthesis of the model dipeptides N-tert-butyloxycarbonylalanylphenylalanine methyl ester and N-benzyloxycarbonylvalylglycine methyl ester.A series of negative qualities, which make their use difficult, were noticed in these ethers.A more convenient modification of the already known method for the production of the esters is proposed.In this method 3-nitro-4-chlorobenzyl alcohol, which is the key product forthe production of 1-hydroxybenzotriazole fixed on a polystyrene matrix, can be synthesized with a high yield and a high degree of purity by the reduction of the corresponding aldehyde with aluminum isopropoxide.
- Grigor'ev, E. I.,Zhil'tsov, O. S.A
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p. 1774 - 1777
(2007/10/02)
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- HETEROCYCLIC COMPOUNDS
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Compounds of Formula I are described STR1 in which X and Y are independently--NH--,--O--or--S--; Z may be a pyrimidine, triazine, triazole, thiazole, thiadiazole ring. The methods of preparation are described. The compounds are useful as antipeptic ulcer agents.
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- "Wolf and lamb" reactions: Equilibrium and kinetic effects in multipolymer systems
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Two reagents reacting avidly with each other in solution are rendered mutually inactive by attaching each to a separate batch of insoluble polymer. Two-stage reactions in which a soluble reagent reacts first with one polymeric reagent and the product with the second polymeric reagent afford advantages over analogous reactions in solution. In acylation reactions of carbon acids, the simultaneous use of a polymeric strong base and a polymeric acylating reagent proved to be superior to the use of soluble reagents, both for bringing about quantitative acylations and for coping with undesirable side reactions. New polymeric strong bases were prepared: polymeric trityllithium, para-substituted trityllithium polymers, and polymeric lithium diisopropylamide. Active esters of polymeric o-nitrophenol and N-1-hydroxybenzotriazole were used as acylation reagents. The scope and limitation of these reactions and their application to general multiphase systems are discussed.
- Cohen,Kraus,Patchornik
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p. 7620 - 7629
(2007/10/02)
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