- Stereoselective Modification of N-(α-Hydroxyacyl)-glycinesters via Palladium-Catalyzed Allylic Alkylation
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N-(α-Hydroxyacyl)-glycinesters can be used as excellent nucleophiles in Pd-catalyzed allylic alkylation. The method allows for the stereoselective introduction of a wide range of side chains, including highly functionalized ones. Both diastereomers can be accessed through variation of the reaction conditions. Furthermore, the use of stannylated carbonates introduces vinylstannane motifs, which are eligible for subsequent C-C coupling reactions.
- Horn, Alexander,Kazmaier, Uli
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supporting information
p. 4595 - 4599
(2019/06/27)
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- Alternating Sequence Controlled Copolymer Synthesis of α-Hydroxy Acids via Syndioselective Ring-Opening Polymerization of O-Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators
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The ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) can give diverse poly(α-hydroxy acid)s (PAHAs) with different functional groups because of easy modification of the side group of OCAs, which can extend applications of PAHAs widely. The stereoselective polymerization of O-carboxyanhydrides and further sequence controlled alternating copolymerization of OCAs were still big challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest Pr value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and Tyr(Bn)OCA, and alternating copolymerization of LacOCA and PheOCA was also achieved.
- Sun, Yangyang,Jia, Zhaowei,Chen, Changjuan,Cong, Yong,Mao, Xiaoyang,Wu, Jincai
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p. 10723 - 10732
(2017/08/15)
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- Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids
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An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids.
- Stuhr-Hansen, Nicolai,Padrah, Shahrokh,Str?mgaard, Kristian
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supporting information
p. 4149 - 4151
(2014/07/22)
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- A PROCESS FOR PREPARATION OF PYRROLES HAVING HYPOLIPIDEMIC HYPOCHOLESTEREMIC ACTIVITIES
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The present invention provides pyrroles having hypolipidemic hypocholesteremic activities. The invention provides saroglitazar and its pharmaceutically acceptable salts, hydrates, solvates, polymorphs or intermediates thereof. The invention also provides a process for the preparation of saroglitazar. The invention further provides intermediates as well process for preparation thereof.
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- Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids
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An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids.
- Stuhr-Hansen, Nicolai,Padrah, Shahrokh,Str?mgaard, Kristian
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p. 4149 - 4151
(2015/02/02)
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- Enantioselective reduction of 3-aryl-2-oxo-propanoic acids: A comparison of enzymatic and transition-metal-catalyzed methods
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Phenyllactic acids are important constituents of depsipeptides, which are a large class of natural products expressing a wide range of biological activities. Despite there being several methods for the enantioselective synthesis of α-hydroxy acids, almost no studies are available addressing the substrate selectivity of transition-metal and enzyme-catalyzed methods for the preparation of substituted phenyllactic or more general aryllactic acids. We report herein comparative results for Rh-DiPAMP (DiPAMP = 1,2-ethandiylbis[(o- methoxyphenyl)phenylphosphane]) and lactate dehydrogenase catalyzed enantioselective reductions of several 3-aryl-2-oxopropanoic acids. Phenyllactic acids are important constituents of depsipeptides, which are a large class of natural products expressing a wide range of biological activities. A comparative study of transition-metal and lactate dehydrogenase catalyzed enantioselective reductions of several 3-aryl-2-oxopropanoic acids as valuable sources for enantiomerically pure phenyllactic acids is described. Copyright
- Luettenberg, Sebastian,Ta, Tien Dat,Von Der Heyden, Jan,Scherkenbeck, Juergen
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supporting information
p. 1824 - 1830
(2013/06/04)
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- 4,4-Dimethyl-1,2,3,4-tetrahydroquinoline-based PPARα/γ agonists. Part I: Synthesis and pharmacological evaluation
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Type-2 diabetes (T2D) is a complex metabolic disease characterized by insulin resistance in the liver and peripheral tissues accompanied by a defect in pancreatic β-cell. Since their discovery three subtypes of Peroxisomes Proliferators Activated Receptors were identified namely PPARα, PPARγ and PPARβ/(δ). We were interested in designing novel PPARγ selective agonists and/or dual PPARα/γ agonists. Based on the typical topology of synthetic PPAR agonists, we focused our design approach on 4,4-dimethyl-1,2,3,4-tetrahydroquinoline as novel cyclic tail.
- Parmenon, Cecile,Guillard, Jerome,Caignard, Daniel-Henri,Hennuyer, Nathalie,Staels, Bart,Audinot-Bouchez, Valerie,Boutin, Jean-Albert,Dacquet, Catherine,Ktorza, Alain,Viaud-Massuard, Marie-Claude
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p. 1617 - 1622
(2008/09/19)
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- Synthesis of a peroxime proliferator activated receptor (PPAR) α/γ agonist via stereocontrolled Williamson ether synthesis and stereospecific SN2 reaction of S-2-chloro propionic acid with phenoxides
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The stereospecific synthesis of the PPAR α/γ agonist 1 was accomplished via ethylation of the optically pure trihydroxy derivative 6, itself derived via an enzymatic resolution. The ethylation can be accomplished without epimerization only under strict control of the reaction conditions and the choice of base (sodium tert-amylate), temperature (-30°C), order of addition, and solvent (DMF). The key diastereospecific SN2 reaction of the phenol 4 with S-2-chloropropionic acid is best achieved via the sodium phenoxide of 4 derived from Na0 as the reagent of choice. The structure elucidation and key purification protocols to achieve pharmaceutical purity will also be described
- Aikins, James A.,Haurez, Michael,Rizzo, John R.,Van Hoeck, Jean-Pierre,Brione, Willy,Kestemont, Jean-Paul,Stevens, Christophe,Lemair, Xavier,Stephenson, Gregory A.,Marlot, Eric,Forst, Mindy,Houpis, Ioannis N.
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p. 4695 - 4705
(2007/10/03)
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- Process for the preparation of new antidiabetic agents
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The present invention relates to an improved process for the preparation of novel antidiabetic compounds having formula (1) where R1represents hydrogen or lower alkyl group and X represents hydrogen or halogen atom.
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- Synthesis of microcin SF608
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The first total synthesis of aquatic peptide microcin SF608 is described. Coupling of L-Hpla with the dipeptide L-Phe-L-Choi followed by coupling with agmatine and a deprotection step gave microcin SF608. In addition, the levorotatory character of L-Hpla (5) was thoroughly established, and the conformational analysis of L-Choi containing peptides 1 and 8-10 was performed using NMR spectroscopy to examine the cis-trans isomer equilibrium of the L-Phe-L-Choi amide bond.
- Valls, Nativitat,Vallribera, Merce,Lopez-Canet, Meritxell,Bonjoch, Josep
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p. 4945 - 4950
(2007/10/03)
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