- Revised stereochemistry of ceramide-trafficking inhibitor HPA-12 by X-ray crystallography analysis
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In response to Berke?'s report revising the stereochemistry of HPA-12, an important ceramide-trafficking inhibitor that was discovered and synthesized and its stereochemistry determined in 2001, the synthesis and the stereochemistry were reinvestigated. A large-scale synthetic method for HPA-12 based on a Zn-catalyzed asymmetric Mannich-type reaction in water was developed. Single crystals of HPA-12 for X-ray crystallographic analysis were obtained from ethyl propionate/n-hexane, and the stereochemistry was definitely determined to be 1R,3S, consistent with Berke?'s revised structure.
- Ueno, Masaharu,Huang, Yi-Yong,Yamano, Akihito,Kobayashi, Shu
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Read Online
- Highly Functionalized Organolithium Reagents for Enantiomerically Pure α-Amino Acid Synthesis
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(Equation presented) Highly functionalized L-serine-derived organolithium reagents have been generated and reacted with a variety of electrophiles, delivering novel enantiomerically pure adducts. These adducts were then converted into homochiral amino alcohols and novel nonproteinogenic α-amino acids, including an aspartic acid mimic that has been synthesized in an enantiomerically pure form for the first time.
- Kenworthy, Martin N.,Kilburn, John Paul,Taylor, Richard J. K.
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Read Online
- CRYSTALLINE FORMS OF A PYRROLIDONE DERIVATIVE USEFUL IN THE TREATMENT OF ALZHEIMER'S DISEASE AND PREPARATION THEREOF
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The present invention provides processes to manufacture crystalline N-[(3S)-1-[4-[(3-fluorophenyl)methoxy]phenyl]-5-oxo-pyrrolidin-3-yl]acetamide. Also disclosed are polymorphic forms of said compound as well as compounds useful as intermediates in the methods of the invention.
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Page/Page column 19
(2015/05/19)
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- Efficient and Selective Cu/Nitroxyl-Catalyzed Methods for Aerobic Oxidative Lactonization of Diols
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Cu/nitroxyl catalysts have been identified that promote highly efficient and selective aerobic oxidative lactonization of diols under mild reaction conditions using ambient air as the oxidant. The chemo- and regioselectivity of the reaction may be tuned by changing the identity of the nitroxyl cocatalyst. A Cu/ABNO catalyst system (ABNO = 9-azabicyclo[3.3.1]nonan-N-oxyl) shows excellent reactivity with symmetrical diols and hindered unsymmetrical diols, whereas a Cu/TEMPO catalyst system (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl) displays excellent chemo- and regioselectivity for the oxidation of less hindered unsymmetrical diols. These catalyst systems are compatible with all classes of alcohols (benzylic, allylic, aliphatic), mediate efficient lactonization of 1,4-, 1,5-, and some 1,6-diols, and tolerate diverse functional groups, including alkenes, heterocycles, and other heteroatom-containing groups.
- Xie, Xiaomin,Stahl, Shannon S.
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supporting information
p. 3767 - 3770
(2015/04/14)
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- DIAMINE DERIVATIVES
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A compound represented by formula (1):Q1-Q2-To-N(R1) -Q3-N(R2)-T1-Q4 [wherein R1 and R2 are hydrogen atoms or the like; Q1 is a saturated or unsaturated, 5- or 6- membered cyclic hydrocarbon group which may be substituted, or the like; Q2 is a single bond or the like; Q3 represents the following group: (wherein Q5 is an alkylene group having 1 to 8 carbon atoms, or the like); and T0 and T1 are carbonyl groups or the like], a salt thereof, a solvate thereof, or an N-oxide thereof. The compound is useful as an agent for preventing and/or treating cerebral infarction, cerebral embolism, myocardial infarction, angina pectoris, pulmonary infarction, pulmonary embolism, Buerger's disease, deep venous thrombosis, disseminated intravascular coagulation syndrome, thrombus formation after artificial valve or joint replacement, thrombus formation and reocclusion after angioplasty, systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), thrombus formation during extracorporeal circulation, or blood clotting upon blood drawing.
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Page/Page column 164-165
(2008/06/13)
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- Diamine derivatives
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A compound represented by the general formula (1): Q1-Q2-T0-N(R1)-Q3-N(R2)-T1-Q4??(1) wherein R1 and R2 are hydrogen atoms or the like; Q1 is a saturated or unsaturated, 5- or 6-membered cyclic hydrocarbon group which may be substituted, or the like; Q2 is a single bond or the like; Q3 is a group in which Q5 is an alkylene group having 1 to 8 carbon atoms, or the like; and T0 and T1 are carbonyl groups or the like; a salt thereof, a solvate thereof, or an N-oxide thereof. The compound is useful as an agent for preventing and/or treating cerebral infarction, cerebral embolism, myocardial infarction, angina pectoris, pulmonary infarction, pulmonary embolism, Buerger's disease, deep venous thrombosis, disseminated intravascular coagulation syndrome, thrombus formation after valve or joint replacement, thrombus formation and reocclusion after angioplasty, systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), thrombus formation during extracorporeal circulation, or blood clotting upon blood drawing.
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- Highly functionalised organolithium and organoboron reagents for the preparation of enantiomerically pure α-amino acids
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Homochiral, highly functionalised organolithium reagents derived from l-serine have been generated and reacted with electrophiles. The novel enantiomerically pure adducts thus obtained were then converted, through β-amino alcohols, into novel non-proteinogenic α-amino acids. The methodology also made available a novel boronic acid which was then employed as a Suzuki cross-coupling partner, elaborating a new pathway to phenylalanine analogues.
- Barfoot, Christopher W.,Harvey, Joanne E.,Kenworthy, Martin N.,Kilburn, John Paul,Ahmed, Mahmood,Taylor, Richard J.K.
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p. 3403 - 3417
(2007/10/03)
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- DIAMINE DERIVATIVES
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A compound represented by the general formula (1):Q1-Q2-T0-N(R1)-Q3-N(R2)-T1-Q4 wherein R1 and R2 are hydrogen atoms or the like; Q1 is a saturated or unsaturated, 5- or 6- membered cyclic hydrocarbon group which may be substituted, or the like; Q2 is a single bond or the like; Q3 is a group in which Q5 is an alkylene group having 1 to 8 carbon atoms, or the like; and T0 and T1 are carbonyl groups or the like; a salt thereof, a solvate thereof, or an N-oxide thereof. The compound is useful as an agent for preventing and/or treating cerebral infarction, cerebral embolism, myocardial infarction, angina pectoris, pulmonary infarction, pulmonary embolism, Buerger's disease, deep venous thrombosis, disseminated intravascular coagulation syndrome, thrombus formation after valve or joint replacement, thrombus formation and reocclusion after angioplasty, systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), thrombus formation during extracorporeal circulation, or blood clotting upon blood drawing.
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- A new entry to polyfunctionalized 4,5-trans disubstituted oxazolidin-2-ones from L-aspartic acid
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A straightforward synthesis of enantiomerically pure (4R,5S)-5-oxazolidinecarboxylic acid, 2-oxo-4-[(t-butyldimethyl-silyloxy)methyl]-, benzyl ester and of (4S,5S)-4-oxazolidinecarboxylic acid, 2-oxo-5-[(t-butyldimethylsilyloxy)methyl]-, benzyl ester was envisaged starting from readily available L-aspartic acid. The key step is the diastereoselective addition of iodine with the introduction of a new stereogenic centre.
- Luppi, Gianluigi,Tomasini, Claudia
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p. 797 - 800
(2007/10/03)
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- Syntheses of four unusual amino acids, constituents of cyclomarin A
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The stereoselective syntheses of four unusual amino acids, constituents of cyclomarin A, are described. The protected N-methylhydroxyleucine 2 was synthesized using Evans' asymmetric azide-transfer reaction. The unusual amino acid 3 was prepared via diastereoselective methylation of the L-aspartic acid derived lactone 13. The stereoselective formation of threo-β-methoxyphenylalanine 4 was performed via aldol reaction using Scho?llkopf's chiral glycine enolate. The synthesis of N-reverse prenylated tryptophane 5 was achieved by the AQN ligand-promoted Sharpless regioreversed asymmetric aminohydroxylation protocol.
- Sugiyama, Hideyuki,Shioiri, Takayuki,Yokokawa, Fumiaki
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p. 3489 - 3492
(2007/10/03)
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- Enantioselective synthesis of 2-isocephem and 2-isooxacephem antibiotics
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The azido lactone 8 was prepared in a highly stereoselective manner by introduction of an azide function to the lactone 6 derived from L-aspartic acid, and then was converted into (2S,3S)-3-amino-2-azido-4-hydroxybutanoic acid 4. Four-component condensation of the amino acid 4, p-nitrobenzyl isocyanide and formaldehyde or 2,2-diethoxyacetaldehyde furnished the corresponding 3,4-cis-azetidinone 16 or 26 in excellent yield. 3-Methoxy-2-isooxacephalosporin was prepared by the intramolecular acylation of imidazolide 23 derived from compound 16. 3-Unsubstituted 2-isocephem and 2-isooxacephem analogues were prepared from the azetidinone 26.
- Nitta, Hajime,Ueda, Ikuo,Hatanaka, Minoru
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p. 1793 - 1798
(2007/10/03)
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- Diastereoselective reactions of Grignard reagents with chiral amino lactols derived from L-aspartic acid
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Nucleophilic additions to chiral amino lactols obtained from L-aspartic acid containing a chiral α-silyloxymethyl function by simple Grignard reagents exhibited high stereoselectivity to provide the corresponding optically active amino alcohols containing three contiguous stereogenic centers. The mechanistic origin of the asymmetric induction is rationalized based on chelation controlled models.
- Yoda,Nakagami,Takabe
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p. 169 - 172
(2007/10/02)
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- Isoindoline derivatives
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Optically active 8-methoxyquinolonecarboxylic acids represented by the formula (I) wherein R1 is lower alkyl have been found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. The compounds may be synthesized from novel optically active intermediates.
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