- PRACTICAL ASYMMETRIC SYNTHESIS OF AKLAVINONE
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A practical synthesis of (+)-aklavinone, the aglycone of antitumor antibiotic aclacinomycin A, is achieved by using the asymmetric aldol reaction of 6a to 10a as the key step.
- McNamara, James M.,Kishi, Yoshito
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- A mild, efficient approach to 3-acylfurans: A short synthesis of perilla ketone
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Several 3-acylfurans 3 were prepared in excellent yield using a one-pot procedure involving the palladium-catalyzed cross-coupling of commercially available acid chlorides with tributyl(3-furyl)-stannane 2 at room temperature.
- Bailey
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- Bispentiptycenyl-N-Heterocyclic Carbene (NHC) Gold Complexes: Highly Active Catalysts for the Room Temperature Hydration of Alkynes
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The virtually quantitative, room temperature hydration of various terminal and internal alkynes in methanol/water requires between 0.01–0.05 molpercent of [AuCl(NHC)] activated with 1.5 equiv. of silver triflate and 45 equiv. of triflic acid (both relative to gold complex) with ton of up to 300.000. Iptycenyl-substituted NHC ligands play the key role and the most efficient NHC ligand is characterized by a hemispherical shape formed by two N-pentiptycenyl substituents. (Figure presented.).
- Bergmann, Marvin,Heidrich, Maximillian,Müller-Borges, Dorian,Plenio, Herbert
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p. 3572 - 3578
(2018/09/22)
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- Synthesis, structure and pyrolysis of stabilised phosphonium ylides containing saturated oxygen heterocycles
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A range of twelve stabilised phosphonium ylides containing tetrahydrofuran, tetrahydropyran or 2,2-dimethyl-1,3-dioxolane rings have been prepared and fully characterised, including one X-ray structure determination of each type. The X-ray structures confirm the P=C and C=O functions to be syn and all the compounds undergo thermal extrusion of Ph3PO to give the corresponding alkynes. In some cases there is also competing loss of Ph3P to give different carbene-derived products and evidence has been obtained for the generation of 2-phenyloxete in this way. Raising the pyrolysis temperature leads in several cases to new secondary reactions of the alkyne products involving a sequence of alkyne to vinylidene isomerisation, intramolecular CH insertion, and retro Diels Alder reaction.
- Aitken, R. Alan,Karodia, Nazira,McCarron, Hollie B.,Rouxel, Cécile,Sahabo, Nina,Slawin, Alexandra M. Z.
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p. 1794 - 1804
(2016/02/10)
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- Stereoselective total synthesis of (-)-nupharamine utilizing an α-chlorosulfide and a sulfinimine for C-C bond formation
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An efficient stereoselective synthesis of the nuphar alkaloid, (-)-nupharamine, is reported. The key features include the Lewis acid catalyzed reaction of an α-chlorosulfide with a silyl ketene acetal for C-C bond formation, creation of the stereocenter at C2 by a diastereoselective reaction of allyl indium with a sulfinimine and reductive amination for the introduction of the C6 stereocenter of the piperidine ring.
- Raghavan, Sadagopan,Rajendar, Sheelamanthula
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p. 131 - 137
(2015/12/30)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Feruloylbenzotriazole and weinreb amide as bioinspired building blocks: A reactivity study towards O-, N-, S-, and C-nucleophiles
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A versatile route for the conversion of ferulic acid into biologically relevant molecules is presented. The compatibility of a number of protection and activation strategies with the 1,2-addition of a variety of O-, N-, S-, and C-nucleophiles to ferulic acid is evaluated. In particular, this report contains the first systematic study of the addition of (hetero)aryllithium reagents to 3-phenylpropenoyl Weinreb amides. The relevance of this "bioinspired" method is illustrated by the synthesis of a number of natural products or analogues, such as zingerone, curcuminoids, and (heteroaryl) chalcones. Feruloylbenzotriazole and Weinreb amide were converted into an array of biologically relevant molecules by addition of O-, N-, S-, and C-nucleophiles. The relevance of this bioinspired approach is illustrated by the synthesis of a number of natural products or analogues, such as zingerone, (heteroaryl) chalcones, and curcuminoids. Copyright
- Roman, Bart I.,Monbaliu, Jean-Christophe,De Coen, Laurens M.,Verhasselt, Sigrid,Schuddinck, Bart,Van Hoeylandt, Evelien,Stevens, Christian V.
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p. 2594 - 2611
(2014/05/06)
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- Functionalized 3(2H)-furanones via photooxygenation of (β-keto)-2- substituted furans: Application to the biomimetic synthesis of merrekentrone C
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Photooxygenation of (β-keto)-2-substituted furans leads, in a one pot operation, to functionalized 3(2H)-furanones with good to excellent yields. This methodology was applied as a key-step to the concise and biomimetic synthesis of the sesquiterpene merre
- Gryparis, Charis,Lykakis, Ioannis N.,Efe, Christina,Zaravinos, Ioannis-Panayotis,Vidali, Theonymphi,Kladou, Eugenia,Stratakis, Manolis
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supporting information; experimental part
p. 5655 - 5658
(2011/09/16)
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- The palladium-catalyzed aerobic kinetic resolution of secondary alcohols: Reaction development, scope, and applications
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The first palladium-catalyzed enantioselective oxidation of secondary alcohols has been developed, utilizing the readily available diamine (-)-sparteine as a chiral ligand and molecular oxygen as the stoichiometric oxidant. Mechanistic insights regarding the role of the base and hydrogen-bond donors have resulted in several improvements to the original system. Namely, addition of cesium carbonate and tert-butyl alcohol greatly enhances reaction rates, promoting rapid resolutions. The use of chloroform as solvent allows the use of ambient air as the terminal oxidant at 23°C, resulting in enhanced catalyst selectivity. These improved reaction conditions have permitted the successful kinetic resolution of benzylic, allylic, and cyclopropyl secondary alcohols to high enantiomeric excess with good-toexcellent selectivity factors. This catalyst system has also been applied to the desymmetrization of meso-diols, providing high yields of enantioenriched hydroxyketones.
- Ebner, David C.,Bagdanoff, Jeffrey T.,Ferreira, Eric M.,McFadden, Ryan M.,Caspi, Daniel D.,Trend, Raissa M.,Stoltz, Brian M.
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supporting information; experimental part
p. 12978 - 12992
(2010/06/19)
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- THIAZOLIDINONES, OXAZOLIDINONES, AND PYRROLIDINONES FOR HBV
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The present invention relates to certain single-enantiomer pyrrazol-4-yl derivatives of thiazolidinones, oxazolidinones, and pyrrolidinones which are useful in the treatment of Hepatitis B virus.
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Page/Page column 25
(2010/11/25)
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- ANTIVIRAL AGENT
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The present invention provides an integrase inhibitor. The inventors have have found the following compound of formula (I) possessing an integrase inhibitory activity. (wherein, R C and R D taken together with the neighboring carbon atoms form a ring which may be a condensed ring, Y is hydroxy, mercapto or amino; Z is O, S or NH ; R A is a group shown by (wherein, C ring is N-containing aromatic heterocycle) or the like)
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- Preparation of substituted aromatic compounds
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A process for preparing compounds of the formula (II), where the substituents R1 to R5 are each independently H, CH3, straight-chain or branched C1-C8-alkyl, CH(OC1-C5-alkyl)2, CH(C1-C5-alkyl)(OC1-C5-alkyl), CH2(OC1-C5-alkyl), CH(CH3)(OC1-C5-alkyl), C1-C8-alkoxy, N(C1-C5-alkyl)2, phenyl, substituted phenyl, aryl, heteroaryl, S(C1-C5-alkyl) or a radical Caryl, alkyl, and the symbols X1 to 5 are each carbon or a maximum of two neighboring X1-5 are nitrogen or X1R1 and X2R2 together are O, NH, N(C1-C5-alkyl), N(C═O—C1-C5-alkyl), N(SiR3)2 or S, or where neighboring radicals R1 to R5 form the following structural unit, where X6 to X9 and R6 to R9 have the same meaning as X1 to X5 and R1 to R5 which comprises reacting chloro- or fluoroaromatics of the formula (I) with carbon electrophiles and lithium metal.
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- FURAN AND PYRROLE CONTAINING LIPOXYGENASE INHIBITING COMPOUNDS
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Substituted furan and pyrrole compounds which are useful in inhibiting lipoxygenase enzymes, particularly 5-lipoxygenase.
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- Additions of Alkyllanthanum Triflates to Carbonyl Compounds: Reactive Organometallic Nucleophiles
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Addition of alkyl- or aryllithium compounds to lanthanum(III) triflate in ethereal solvents produces the title reagents 2 that undergo nucleophilic addition to carbonyl compounds under mild conditions.These reagents resemble alkylcerium halides in their reactions with enolizable carbonyl compounds but are more reactive.In particular, they are useful for the conversion of hindered, tertiary amides to the ketones. 1H NMR spectroscopy was employed to clarify mechanistic aspects of this addition process.The title reagents actually appear to be a mixture of several species; formulation of their structure has proven elusive.However, in the presence of a tertiary amide, these species react to give a single, tetrahedral intermediate, which is quite stable in solution.
- Collins, Scott,Hong, Yaping,Hoover, Gordon J.,Veit, Jennifer R.
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p. 3565 - 3568
(2007/10/02)
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- Substituted furan compounds which are useful in inhibiting lipoxygenase enzymes, particularly 5-lipoxygenase
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Substituted furan and pyrrole compounds of formula (I) which are useful in inhibiting lipoxygenase enzymes, particuarly 5-lipoxygenase.
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