- Multiple Absolute Stereocontrol in Cascade Lactone Formation via Dynamic Kinetic Resolution Driven by the Asymmetric Transfer Hydrogenation of Keto Acids with Oxo-Tethered Ruthenium Catalysts
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A straightforward asymmetric construction of chiral fused γ- and δ-lactones containing multiple contiguous stereocenters was successfully developed by either (1) the dynamic kinetic resolution-asymmetric transfer hydrogenation (DKR-ATH) reaction using oxo
- Touge, Taichiro,Sakaguchi, Kazuhiko,Tamaki, Nao,Nara, Hideki,Yokozawa, Tohru,Matsumura, Kazuhiko,Kayaki, Yoshihito
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supporting information
p. 16354 - 16361
(2019/10/16)
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- A water-soluble initiating agent and its preparation
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A water-soluble initiator and preparation thereof belong to the technical field of high-molecular compounds. The water-soluble initiator has the structural formula (img file='DDA000423558880000011. TIF' wi='496' he='320'/) shown in the specification, wher
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Paragraph 0021
(2017/02/23)
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- Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
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The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
- Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
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supporting information
p. 17662 - 17668
(2015/02/02)
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- Practical preparation of enantiopure 2-methyl-azetidine-2-carboxylic acid; a γ-turn promoter
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A robust and practical synthesis of each enantiomer of 2-methyl-azetidine- 2-carboxylic acid, based on the use of (S)-phenylglycinol as resolving agent, is described. This synthesis affords practical quantities of this quaternary amino acid suitably N- an
- Drouillat, Bruno,Wright, Karen,Marrot, Jerome,Couty, Francois
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scheme or table
p. 690 - 696
(2012/09/21)
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- Asymmetric Michael addition of α-nitro-ketones using catalytic peptides
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Peptide-based catalysts have been developed that promote the asymmetric Michael addition of nitroalkanes. The most effective peptides contain a β-turn structural element as well as a basic histidine and an arylsulfonamide-protected arginine. Excellent yields with enantioselectivities of up to 74% ee have been observed.
- Linton, Brian R.,Reutershan, Michael H.,Aderman, Christopher M.,Richardson, Elizabeth A.,Brownell, Kristen R.,Ashley, Charles W.,Evans, Catherine A.,Miller, Scott J.
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p. 1993 - 1997
(2007/10/03)
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- Inclusion complexes of EMPO derivatives with 2,6-di-O-methyl-β- cyclodextrin: Synthesis, NMR and EPR investigations for enhanced superoxide detection
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The free radical trapping properties of eight 5-alkoxycarbonyl-5-methyl-1- pyrroline N-oxide (EMPO) type nitrones and those of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) were evaluated for trapping of superoxide anion radicals in the presence of 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). 1H-NMR titrations were performed to determine both stoichiometries and binding constants for the diamagnetic nitrone-DM-β-CD equilibria. EPR titrations were then performed and analyzed using a two-dimensional EPR simulation program affording 1: 1 and 1: 2 stoichiometries for the nitroxide spin adducts with DM-β-CD and the associated binding constants after spin trapping. The nitroxide spin adducts associate more strongly with DM-β-CD than the nitrones. The ability of the nitrones to trap superoxide, the enhancement of the EPR signal intensity and the supramolecular protection by DM-β-CD against sodium l-ascorbate reduction were evaluated. The Royal Society of Chemistry 2006.
- Bardelang, David,Rockenbauer, Antal,Karoui, Hakim,Finet, Jean-Pierre,Biskupska, Inga,Banaszak, Karol,Tordo, Paul
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p. 2874 - 2882
(2008/02/08)
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- 5-Hydroxy[1,2]oxazinan-3-ones as potential carbapenem and D-ala-D-ala surrogates
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The title compounds are amino acids whose nitrogen atom is enclosed in a six-membered cyclic hydroxamate bearing a C5-hydroxyl group. They belong to a proposed new family of antibacterial agents targeted to the penicillin receptor. The glycine and alanine members of the family have been synthesized, as racemates, in seven steps from the four-carbon synthon diketene and the tert-butyl esters of N-hydroxyglycine and N-hydroxyalanine. Numerous alternatives to diketene have also been examined, but these lead mainly to five-membered cyclic hydroxamates. The theoretical considerations that have led to this synthetic programme are discussed in some detail. They include analysis of the structures of natural and unnatural penicillin surrogates, analysis of the penicillin pharmacophore, and a treatment of the chemical reaction with which penicillin blocks bacterial cell wall synthesis. The glycine derivative exhibits marginal but real activity vs. Micrococcus luteus. The alanine derivative, which more closely resembles D-ala-D-ala, is fifty times more active. Two five-membered structural isomers of the glycine derivative are inactive.
- Wolfe, Saul,Akuche, Christiana,Ro, Stephen,Wilson, Marie-Claire,Kim, Chan-Kyung,Shi, Zheng
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p. 915 - 936
(2007/10/03)
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- Oxazinones having antibacterial activity
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The invention relates to novel oxazinones designed to bind to the penicillin receptor, methods of synthesizing the compounds, and the use of the compounds as antibacterial agents. The compounds have the general formula (I) Preferably the compounds have a carboxyethyl or a substituted carboxymethyl substituent at the 2-position and a hydroxyl group at the 5-position and have a molecular shape suitable for binding to and reacting with the active site of a pencillin-recognizing enzyme. The compounds are synthesized by condensing a carboxyl-protected N-hydroxy amino acid with a 3-hydroxyprotected-4-bromobutanoic acid to form a a doubly protected N-hydroxy N-acylamino acid, which is cyclized with an organic base to yield a doubly protected 1,2-oxazin-3-one. The protecting groups are then removed to provide an antibacterial agent.
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- Cyclofunctionalization and free-radical-based hydrogen-transfer reactions. An iterative reaction sequence applied to the synthesis of the C7-C16 subunit of zincophorin
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The strategy considered herein features an iodocyclofunctionalization/hydrogen-transfer reaction sequence for the elaboration of propionate motifs. Proceeding with excellent yield and diastereo-selectivity, the synthetic sequence proposed gives access to the anti-anti dipropionate motif when the reduction step is performed under the control of the exocyclic effect. The tandem sequence is applied successfully to the synthesis of the C7-C16 subunit of zincophorin, and iteration of the process gives the desired anti-anti-anti-anti polypropionate stereopentad. Modifications of the reaction sequence - including phenylselenocyclofunctionalization, carbonate hydrolysis, and chelation-controlled radical reduction reactions - lead to the formation of the anti-syn dipropionate motif with remarkable diastereocontrol.
- Guindon,Murtagh,Caron,Landry,Jung,Bencheqroun,Faucher,Guerin
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p. 5427 - 5437
(2007/10/03)
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- Solvent dependent photochemical reactions of 3-(2-alkylphenyl)-2,2- dimethyl-3-oxopropanoates and their related compounds
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Photochemical reactions of methyl 3-(o-alkylphenyl)-2,2-dimethyl-3- oxopropanoates in hexane gave only the corresponding benzocyclobutenols. However, when irradiation was carried out in methanol, 3-oxonaphthalenones were produced together with the benzocyclobutenols. The ratio of benzocyclobutenol to naphthalenone depends on the bulkiness of the alkyl group in the ortho position. Intermediary 1,4-diradicals or dienols were efficiently trapped by oxygen to afford the corresponding peroxides and/or oxygenated compounds derived from the peroxides.
- Saito, Masaichi,Kamei, Yumiko,Kuribara, Kanae,Yoshioka, Michikazu,Hasegawa, Tadashi
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p. 9013 - 9018
(2007/10/03)
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- Compounds for treating hypertension
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Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
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- COMPOUNDS FOR TREATING HYPERTENSION
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Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
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- Syn isomer of 7-[2-cyclo(lower) alkoxyimino-2-(2-amino-or substituted aminothiazol-4-yl)acetamido]-3-lower alkanoyloxymethyl or heterocyclicthiomethyl-3-cephem-4-carboxylic acid compounds
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Syn isomers of 3-substituted 7-[2-substituted imino-2-substituted acetamido]-3-cephem-4-carboxylic acid and salt bacteriostatic-compounds and pharmaceutical compositions thereof and processes for preparing same.
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- Syn-isomers of 7-[2-alkoxyimino-2-(2-amino-thiazol-4-yl)acetamido]-3-[nitrobenzoyl-, or benzoyl-oxymethyl]-3-cephem-4-carboxylic acid
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New syn-isomers of 3-cephem-4-carboxylic acids having anti-bacterial activities, processes for preparation thereof, pharmaceutical compositions thereof, with the acids being substituted at the 3 position with acyloxymethyl, hydroxymethyl, formyl or heterocyclic thiomethyl groups and at the 7 position with alkoxyiminoacetamido substituted with substituted phenyl or substituted thiazolyl.
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- Syn-isomer of 3,7-disubstituted-3-cephem-4-carboxylic acid compounds and processes for the preparation thereof
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Preparation of pharmaceutical composition comprising, treatment of human and animal diseases with, and compound of, 3,7-disubstituted-3-cephem-4-carboxylic acid.
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- Syn 7-oxoimino substituted derivatives of cephalosporanic acid
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The present invention relates to new syn-isomer of 3,7-disubstituted-3-cephem-4-carboxylic acid compounds and pharmaceutically acceptable salts thereof. More particularly, it relates to new syn-isomer of 3,7-disubstituted-3-cephem-4-carboxylic acid compounds and pharmaceutically acceptable salts thereof which have antibacterial activities and to processes for the preparation thereof, to pharmaceutical composition comprising the same, and to a method of using the same therapeutically in the treatment of infectious diseases in human beings and animals.
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