- 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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supporting information
p. 10723 - 10732
(2017/08/15)
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- Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
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Enantiopure N-benzyloxycarbonyl-protected and free 3-substituted homotaurines were synthesized from naturally occurring amino acids via N-benzyloxycarbonyl protection, Arndt-Eistert homologation, reduction, esterification with thioacetic acid, and oxidation with performic acid. The current method is a convenient, practical, and salt-free method for the synthesis of enantiopure 3-substituted homotaurine with moderate to good yields.
- Zheng, Yongpeng,Xu, Jiaxi
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p. 5197 - 5206
(2014/07/08)
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- Synthesis of enantiopure free and N-benzyloxycarbonyl-protected 3-substituted homotaurines from naturally occurring amino acids
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Enantiopure N-benzyloxycarbonyl-protected and free 3-substituted homotaurines were synthesized from naturally occurring amino acids via N-benzyloxycarbonyl protection, Arndt-Eistert homologation, reduction, esterification with thioacetic acid, and oxidation with performic acid. The current method is a convenient, practical, and salt-free method for the synthesis of enantiopure 3-substituted homotaurine with moderate to good yields.
- Zheng, Yongpeng,Xu, Jiaxi
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p. 5197 - 5206
(2014/12/10)
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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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Page/Page column 27
(2015/01/06)
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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
(2015/02/02)
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- NOVEL ANTIDIABETIC COMPOUNDS
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The present invention provides novel compounds of the general formula (I), wherein the symbols are same as described in specification, their pharmaceutically acceptable salts, their tautomeric forms, their stereoisomers, pharmaceutical compositions containing them, to process and intermediates for the preparation of the above said compounds, having the utility of these compounds in medicine and to methods for their therapeutic use, and their use in the treatment of diabetes and related diseases.
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Page/Page column 83-84
(2010/11/29)
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- Decomposition of copper-amino acid complexes by sodium sulfide
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Sodium sulfide very efficiently removes copper from protected amino acid-copper complexes. The copper in the amino acid complex was reduced to insoluble cuprous sulfide and the free amino acid was released in pure form. This method is very convenient and rapid, requiring only 5-10 min and 0.55-0.75 equiv of sodium sulfide.
- Nowshuddin, Shaik,Reddy, A. Ram
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p. 5159 - 5161
(2007/10/03)
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- PROCESS FOR PREPARING 3-ARYL-2-HYDROXY PROPANOIC ACID DERIVATIVES WITHOUT RESOLUTION
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The present invention discloses an improve process for the preparation of S (-) and R (+) 3-aryl-2-hydroxy propanoic acid derivatives without any resolution involved.
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Page/Page column 10; 11
(2010/02/11)
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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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- Syntheses of amino alcohols and chiral C2-symmetric bisoxazolines derived from O-alkylated R-4-hydroxyphenylglycine and S-tyrosine
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Chiral C2-symmetric bisoxazolines 1b-f and 2b,c, derived from 4′-O-alkylated R-4-hydroxyphenylglycine or S-tyrosine, were prepared. As intermediates, a series of chiral amino alcohols possessing substituted phenolic groups was prepared and fully characterized.
- Caplar, Vesna,Raza, Zlata,Katalenic, Darinka,Zinic, Mladen
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- Process for the preparation of 3-aryl-2-hydroxy propanoic acid
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The present invention relates to an improved process for the preparation of 3-aryl-2-hydroxy propanoic acid derivatives of the formula (1) 1useful as an intermediate for the preparation of many pharmaceutically active compounds.
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- Degradation of azaglycinamido residues in model tripeptides derived from goserelin
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Three model tripeptides, N-acetyl-Tyr-Pro-azaGly-NH2 (NYPaG), Tyr-Pro- azaGly-NH2 (YPaG), and Tyr-Pro-Gly-NH2(YPG), were subjected to a systematic degradation study to get information about the degradation of the azaglycinamido residue The degradation products were characterized with LC- MS. Main degradation products of NYPaG possess partially or totally eliminated azaglycinamido residues, while YPaG and YPG are exhibit cyclo(Tyr- Pro) formation, a diketopiperazine. The influence of the pH on the degradation rate constant k(obs) was investigated for NYPaG and YPaG in the pH range 0.4-11. An U-shaped profile with an inflexion around pH 9 was found for NYPaG while the degradation rate of YPaG was independent of the pH. NYPaG apparently was subject to proton-, solvent-, and hydroxyl-catalyzed degradation reactions whereas YPaG only underwent solvent-catalyzed reactions. Some influence of acetate and phosphate ions on k(obs) was found for YPaG. Arrhenius plots of NYPaG and YPaG were found to be linear. (C) 2000 Wiley-Liss, Inc.
- Hoitink, Marnix A.,Beijnen, Jos H.,Bult, Auke,Damen, J. Mirjam A.,Van Der Houwen, Oeds A. G. J.,Kruijtzer, John A. W.,Tibben, Matthijs M.,Wiese, Gerard,Underberg, Willy J. M.
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p. 108 - 114
(2007/10/03)
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- Selective Inhibition of Benzyl Ether Hydrogenolysis with Pd/C Due to the Presence of Ammonia, Pyridine or Ammonium Acetate
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Ammonia, pyridine and ammonium acetate were found to be extremely effective as inhibitors of Pd/C catalyzed benzyl ether hydrogenolysis.While olefin, Cbz, benzyl ester and azide functionalities were hydrogenated smoothly, benzyl ethers were not cleaved in the presence of these additives.
- Sajiki, Hironao
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p. 3465 - 3468
(2007/10/02)
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- New Reagents to Decompose Copper Complexes of Amino Acids
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The use of N,N-dialkyl-N'-(benzoyl)thioureas in ethanol is an effective method to decompose copper complexes of amino acids.The reaction gives optimal yields, and no racemisation is observed.Furthermore, the recovery of the thiourea derivatives is an important advantage of this method.
- Koenig, Karl-Heinz,Kaul, Lothar,Kuge, Martin,Schuster, Michael
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p. 1115 - 1116
(2007/10/02)
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