- Enantioselective acyl-transfer catalysis by fluoride ions
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The asymmetric nucleophilic catalysis by fluoride ions at a carbon-based electrophile has been demonstrated for the first time. Using a library of ad hoc designed bifunctional phase-transfer catalysts in which both the anion and the cation are directly involved in the reaction, the desymmetrisation of meso-succinic and -glutaric anhydrides is possible.19F NMR spectroscopic studies support the intermediacy of an acyl fluoride intermediate.
- Craig, Ryan,Litvajova, Mili,Cronin, Sarah A.,Connon, Stephen J.
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supporting information
p. 10108 - 10111
(2018/09/18)
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- CYCLOPROPANECARBOXYLIC ACID GPR120 MODULATORS
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The present invention provides compounds of Formula (I): or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are GPR120 G protein coupled receptor modulators which may be used as medicaments
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Page/Page column 0309; 0310
(2017/09/21)
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- PHENYL-(AZA)CYCLOALKYL CARBOXYLIC ACID GPR120 MODULATORS
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The present invention provides compounds of Formula (I): or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are GPR120 G protein-coupled receptor modulators which may be used as medicaments.
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Paragraph 00269
(2016/04/20)
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- AROMATIC RING COMPOUND
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The present invention provides an aromatic ring compound having a melanin-concentrating hormone receptor antagonistic action and useful as an agent for the prophylaxis or treatment of obesity and the like. The present invention relates to a compound represented by the formula wherein each symbol as defined in the specification, or a salt thereof.
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Paragraph 0304
(2015/03/28)
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- (2R,1'S,2'R)- And (2S,1'S,2'R)-3-[2-mono(di,tri)fluoromethylcyclopropyl] alanines and their incorporation into hormaomycin analogues
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Efficient and scalable syntheses of enantiomerically pure (2 R ,1' S ,2' R )- and (2 S ,1' S ,2' R )-3-[2-mono(di,tri)fluoromethylcyclopropyl] alanines 9a - c , as well as allo-D-threonine ( 4 ) and ( 2 S,3R)-β-methylphenylalanine (3), using the Belokon' approach with (S )- and (R )-2-[( N-benzylprolyl)amino]benzophenone [(S)- and (R)-10 ] as reusable chiral auxiliaries have been developed. Three new fluoromethyl analogues of the naturally occurring octadepsipeptide hormaomycin ( 1 ) with (fluoromethylcyclopropyl) alanine moieties have been synthesized and subjected to preliminary tests of their antibiotic activity.
- De Meijere, Armin,Kozhushkov, Sergei I.,Yufit, Dmitrii S.,Grosse, Christian,Kaiser, Marcel,Raev, Vitaly A.
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supporting information
p. 2844 - 2857
(2015/02/19)
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- A new structural motif for bifunctional bronsted acid/base organocatalysis
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"Chemical equation presented" Naturally synthetic: Acid/base catalyst (S)-I can be used in highly enantioselective alcoholytic desymmetrizations of meso anhydrides. For example, the methanolysis of cyclobutane anhydride deriva-tive 2 gave hemiester 3 in 99:1 e.r. (see scheme). Ester 3 was used in a short enantioselective synthesis of (+ )-grandisol.
- Wakchaure, Vijay N.,List, Benjamin
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supporting information; experimental part
p. 4136 - 4139
(2010/08/07)
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- Synthesis of both enantiomers of hemiesters by enantioselective methanolysis of meso cyclic anhydrides catalyzed by α-amino acid-derived chiral thioureas
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(Figure presented) Both ureas and thioureas derived from l- or d-valine act as bifunctional organocatalysts able to induce the enantioselective alcoholysis of mono-, bi-, and tricyclic meso anhydrides. The desymmetrization occurs in near quantitative yields and excellent enantiomeric ratios (up to >99:1) under low catalyst loading. Both enantiomers of the hemiesters can be directly obtained by changing the configuration of the catalyst.
- Manzano, Ruben,Andres, Jose M.,Muruzabal, Maria-Dolores,Pedrosa, Rafael
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supporting information; scheme or table
p. 5417 - 5420
(2010/09/07)
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- Highly enantioselective desymmetrization of meso anhydrides by a bifunctional thiourea-based organocatalyst at low catalyst loadings and room temperature
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(Chemical Equation Presented) Bifunctional (thio)urea-based cinchona alkaloid derivatives have been shown to promote highly efficient enantioselective desymmetrization reactions of meso anhydrides. The most selective of these catalysts is capable of the enantioselective methanolysis of succinic and glutaric anhydride derivatives to form hemiester products with >90% yield and enantiomeric excess at 1 mol % loading and ambient temperature.
- Peschiulli, Aldo,Gun'ko, Yurii,Connon, Stephen J.
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p. 2454 - 2457
(2008/09/19)
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- Dipolar cycloaddition of carbonyl ylides generated from methyl cis-2-diazoacetyl-1-cyclopropanecarboxylates
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Carbonyl ylide generated from methyl cis-3-diazoacetyl-2,2-diphenyl-1- cyclopropanecarboxylate in the presence of Rh2(OAc)4 when brought into reaction of 1,3-dipolar cycloadditionCyrillic small letter YA sign with N-arylmaleimides afforded substituted 4-aryl-7-methoxy-9,9-diphenyl-12-oxa- 4-azatetracyclo-[5.4.1.02,6.08,10]dodecene-3,5,11-triones. Concurrent processes resulted in formation of cycloheptatrienes, hydroxyacetylcyclopropanecarboxylates, and benzophenone. Carbonyl ylide generated from methyl cis-2-diazoacetyl-1-cyclopropanecarboxylate in the same reaction gave rise to exo- and endo-4-aryl-7-methoxy-12-oxa-4-azatetracyclo[5.4. 1.02,6 .08,10] dodecene-3,5,11-triones. 2005 Pleiades Publishing, Inc.
- Molchanov,Diev,Kopf,Kostikov
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p. 194 - 203
(2007/10/03)
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- Synthesis and radical polymerization of various 2-cyclopropylacrylates
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Fourteen new alkyl 2-cyclopropylacrylates 1a-n with various substituents R1-R5 were synthesized from readily available precursors by applying standard transformations such as cyanohydrin formation from an aldehyde, alcoholysis to an α-hydroxycarboxylic ester, oxidation and Wittig methylenation of an α-oxocarboxylic ester. Overall yields ranged from 33 to 54%. A new method for the hydrolysis of dimethyl cyclopropanedicarboxylates to the corresponding half-esters was developed. The α-oxocarboxylates 7g-n were prepared by dirhodium tetraacetate catalyzed cyclopropanation of alkenes 8g-n with methyl or ethyl diazopyruvate in 32-58% yield. The monomers 1a-n were characterized by 1H, 13C NMR spectroscopy, mass spectrometry and elemental analysis. The radical homopolymerizations of 1a-n were carried out with 2,2′- azabisisobutyronitrile (AIBN) as initiator in chlorobenzene at 65 °C. The highest polymer yields were obtained in the polymerizations of If and 1h or 1k and 11, i.e. from monomers with an annelated five- or six-membered ring. In the case of 1h and 1k, both the polymer yields (99 and 98%, respectively) and the glass transition temperatures (Tg) of 57 and 93 °C were significantly higher than those observed for the polymer from 1,1-bis(ethoxycarbonyl)-2-vinylcyclopropane (DECVCP), which was used as a benchmark for the monomer reactivities in the radical polymerizations of all the vinylcyclopropane derivatives 1a-n. The bicyclic monomers 1h and 1k also demonstrated drastically improved reactivities in the radical copolymerization with methyl methacrylate when compared to DECVCP. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- De Meijere, Armin,Bagutski, Viktor,Zeuner, Frank,Fischer, Urs Karl,Rheinberger, Volker,Moszner, Norbert
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p. 3669 - 3678
(2007/10/03)
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- Application of polymer-supported enzymes and reagents in the synthesis of γ-aminobutyric acid (GABA) analogues
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Polymer-supported pig liver esterase was used for the resolution of meso-diesters. The enzyme can be recovered quantitatively from the reaction mixture by filtration and reused without significant loss of activity. Further transformation of the resulting enantiomerically enriched carboxylic acids through the application of polymer-supported reagents and scavengers provides a number of GABA-analogues.
- Baxendale, Ian R.,Ernst, Martin,Krahnert, Wolf-Rüdiger,Ley, Steven V.
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p. 1641 - 1644
(2007/10/03)
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- Solid phase synthesis of diamides as potential bone resorption inhibitors
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Unsymmetrical diamide libraries have been prepared by a general and versatile solid phase route, using diacid templates in combination with aromatic and aliphatic amines chosen with the help of statistical experimental design. The compounds were tested as
- Edvinsson, Karin M.,Hersloef, Margareta,Holm, Patrik,Kann, Nina,Keeling, David J.,Mattsson, Jan P.,Norden, Bo,Shcherbukhin, Vladimir
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p. 503 - 507
(2007/10/03)
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- Enantioselective synthetic approaches to cyclopropane and cyclobutane β-amino acids: Synthesis and structural study of a conformationally constrained β-dipeptide
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Synthetic approaches to carbocyclic compounds, namely cyclopropane and cyclobutane β-amino acids, are presented. One of them is based on enzymatic desymmetrization of meso diesters, leading to the enantioselective production of cis-hemiesters, which afforded β-amino acids through Curtius rearrangements. The enantiomeric excess for the cyclobutane derivatives was 91% whereas the cyclopropanes were obtained in 63% ee. According to another strategy, an enantiomerically pure cyclopropane trans-β-amino acid, bearing a quaternary center, has been synthesized from a homochiral precursor easily available from D-glyceraldehyde. The preparation and structural investigation of the first synthesized cyclobutane containing dipeptide is also described. A hairpin-like conformation of this molecule in the solid state has been demonstrated by X-ray structural analysis, showing crystal packing induced by the presence of the rigid cyclobutane moiety and the formation of intermolecular hydrogen bonds. NMR experiments confirmed that these molecules also tend to produce aggregates in solution. On the contrary, theoretical calculations suggest that intramolecular interactions are important in the gas phase, as expected. Copyright (C) 2000 Elsevier Science Ltd.
- Martin-Vila, Marta,Muray, Elena,Aguado, Gemma P.,Alvarez-Larena, Angel,Branchadell, Vicenc,Minguillon, Cristina,Giralt, Ernest,Ortuo, Rosa M.
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p. 3569 - 3584
(2007/10/03)
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- Practical and Highly Enantioselective Ring Opening of Cyclic Meso-Anhydrides Mediated by Cinchona Alkaloids
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The cinchona alkaloid-mediated opening of prochiral cyclic anhydrides in the presence of methanol leading to optically active hemiesters is described. Very structurally diverse anhydrides are converted into their corresponding methyl monoesters, and either enantiomer can be obtained with up to 99% ee by using quinine or quinidine as directing additive. After the reaction, the alkaloids can be recovered almost quantitatively and reused without loss of enantioselectivity. Additionally, a catalytic protocol which permits the substoichiometric use of quinidine in the presence of easily accessible pentamethylpiperidine (pempidine) is presented.
- Bolm, Carsten,Schiffers, Ingo,Dinter, Christian L.,Gerlach, Arne
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p. 6984 - 6991
(2007/10/03)
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- ATP-sensitive potassium channel openers: Synthesis and antihypertensive activity of 4-bicycloxybenzopyrans
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Synthesis and hypotensive activity of trans-3,4-dihydro-3-hydroxy-4-[(5-oxo-3,4-diazabicyclo[4.1.0]hept-2-en-2 -yl)oxy]-2H-1-benzopyrans and their congeners are described. Compounds (-)-9eB and (-)-20B were highly potent ATP-sensitive potassium channel openers.
- Horino, Haruhiko,Mimura, Tetsuya,Ohta, Masahiro,Kubo, Hideo,Kitagawa, Masayuki
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p. 437 - 442
(2007/10/03)
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- Synthesis of racemic carbocyclic cyclopropanoid nucleoside analogues
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As further representatives of a novel class of carbocyclic nucleoside analogues (±)-cis- and (±)-trans-(2-hydroxymethylcyclopropyl)-uracil, -thymine, and -inosine were synthesized from the corresponding dialkyl 1,2-cyclopropane dicarboxylates.
- Csuk, Rene,Von Scholz, Yvonne
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p. 7193 - 7206
(2007/10/02)
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- Synthesis of Cyclopropyl Carbocyclic Nucleosides
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As representatives of a novel class of carboxylic nucleoside analogues (+/-)-cis-, (-)-cis and (+/-)-trans 9-(2-hydroxymethylcyclopropyl)-adenine (= -methanol) were synthesized from the corresponding dialkyl 1,2-cyclopropane dicarboxylates.
- Csuk, Rene,Scholz, Yvonne von
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p. 10431 - 10442
(2007/10/02)
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- STEREOCHEMISTRY OF THE THERMAL ISOMERIZATIONS OF (2S,3R)-2-METHOXYMETHYL-2,3-DIDEUTERIO-1-(DIDEUTERIOMETHYLENE)CYCLOPROPANE
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The (2S,3R) isomer of 2-methoxymethyl-2,3-dideuterio-1-(dideuteriomethylene)cyclopropane has been synthesized and heated at 198.8o: from the experimentally observed mol fractions of the eight isomers of 2,3,α,α,- and 2,3,3,α-tetradeuterio-2-met
- Baldwin, John E.,Chang, Glenn Eu Chung
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p. 825 - 835
(2007/10/02)
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