- Palladium-Catalyzed Allylic Alkylation of Aldimine Esters with Vinyl-Cyclopropanes to Yield α,α-Disubstituted α-Amino Acid Derivatives
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A synthetically useful approach for the synthesis of functionalized α, α-disubstituted α-amino acid derivatives via palladium-catalyzed 1,7 addition of readily available aldimine esters to vinylcyclopropanes is reported. This methodology was operated under mild conditions, affording α-allylic α-amino esters in good to excellent yields and excellent regio- and stereoselectivity. This transformation displays broad functional-group tolerance and enantioselective allylic alkylation has also been realized using a chiral phosphine ligand to provide the desired product. (Figure presented.).
- Wang, Jiahua,Dai, Zonghao,Xiong, Cheng,Zhu, Jin,Lu, Jinrong,Zhou, Qingfa
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supporting information
p. 5105 - 5111
(2019/11/11)
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- Discovery of (1R,5S)-N-[3-amino-1-(cyclobutylmethyl)-2,3-dioxopropyl]-3- [2(S)-[[[(1,1-dimethylethyl)amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]-6, 6-dimethyl-3-azabicyclo[3.1.0]hexan-2(S)-carboxamide (SCH 503034), a selective, potent, orally bioavailable hepatitis C virus NS3 protease inhibitor: A potential therapeutic agent for the treatment of hepatitis C infection
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Hepatitis C virus (HCV) infection is the major cause of chronic liver disease, leading to cirrhosis and hepatocellular carcinoma, which affects more than 170 million people worldwide. Currently the only therapeutic regimens are subcutaneous interferon-α or polyethylene glycol (PEG)-interferon-α alone or in combination with oral ribavirin. Although combination therapy is reasonably successful with the majority of genotypes, its efficacy against the predominant genotype (genotype 1) is moderate at best, with only about 40% of the patients showing sustained virological response. Herein, the SAR leading to the discovery of 70 (SCH 503034), a novel, potent, selective, orally bioavailable NS3 protease inhibitor that has been advanced to clinical trials in human beings for the treatment of hepatitis C viral infections is described. X-ray structure of inhibitor 70 complexed with the NS3 protease and biological data are also discussed.
- Venkatraman, Srikanth,Bogen, Stéphane L.,Arasappan, Ashok,Bennett, Frank,Chen, Kevin,Jao, Edwin,Liu, Yi-Tsung,Lovey, Raymond,Hendrata, Siska,Huang, Yuhua,Pan, Weidong,Parekh, Tejal,Pinto, Patrick,Popov, Veljko,Pike, Russel,Ruan, Sumei,Santhanam, Bama,Vibulbhan, Bancha,Wu, Wanli,Yang, Weiying,Kong, Jianshe,Liang, Xiang,Wong, Jesse,Liu, Rong,Butkiewicz, Nancy,Chase, Robert,Hart, Andrea,Agrawal, Sony,Ingravallo, Paul,Pichardo, John,Kong, Rong,Baroudy, Bahige,Malcolm, Bruce,Guo, Zhuyan,Prongay, Andrew,Madison, Vincent,Broske, Lisa,Cui, Xiaoming,Cheng, Kuo-Chi,Hsieh, Yunsheng,Brisson, Jean-Marc,Prelusky, Danial,Korfmacher, Walter,White, Ronald,Bogdanowich-Knipp, Susan,Pavlovsky, Anastasia,Bradley, Prudence,Saksena, Anil K.,Ganguly, Ashit,Piwinski, John,Girijavallabhan, Viyyoor,Njoroge, F. George
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p. 6074 - 6086
(2007/10/03)
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- Mimicking enzymatic transaminations: Attempts to understand and develop a catalytic asymmetric approach to chiral α-amino acids
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Attempts are made to build a bridge between asymmetric catalysis and enzymatic reactions by mechanistic investigations and the development of a catalytic and enantioselective approach to amination of α-keto esters by primary amines catalyzed by chiral Lewis acids as a model for transamination enzymes. Different Lewis acids can catalyze the half-transamination of α-keto esters using primary amine nitrogen sources such as pyridoxamine and 4-picolylamine. The mechanistic studies of the Lewis-acid catalyzed half-transamination using deuterium-labelled compounds show the incorporation of deuterium atoms in several positions of the α-amino acid derivative, indicating that the enol of the α-keto ester plays an important role along the reaction path. The catalytic enantioselective reactions are dependent on the pKa-value of the solvent since enantioselectivities were only obtained in solvents with high pKa-values relative to methanol. However, stronger acidic conditions generally gave better yields, but poor enantioselectivities. A series of chiral Lewis acids were screened as catalysts for the enantioselective half-transamination reactions and moderate yields and enantioselectivities of up to 46% ee were obtained.
- Bachmann, Stephan,Knudsen, Kristian Rahbek,Jorgensen, Karl Anker
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p. 2044 - 2049
(2007/10/03)
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- ENANTIOSELECTIVE HYDROLYSIS BY BAKER'S YEAST - II. ESTERS OF N-ACETYL AMINO ACIDS
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D-N-Acetyl amino acid esters were obtained via enantioselective hydrolysis of their racemates by use of fermenting yeast.Evidence is given that proteinases are the enzymes involved.
- Glaenzer, B. I.,Faber, K.,Griengl, H.
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p. 771 - 778
(2007/10/02)
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