- Enantioselective hydrolysis of various racemic α-substituted arylacetonitriles using Rhodococcus sp. CGMCC 0497
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The enantioselective hydrolysis of 17 racemic α-substituted arylacetonitriles by Rhodococcus sp. CGMCC 0497 is described. The corresponding (R)-amides and (S)-acids were obtained with excellent enantiomeric excess in most cases. The effect of steric and electronic factors on the outcome of the reactions are discussed here. The results prove that nitrile-converting enzymes are efficient tools for the synthesis of sterically unencumbered chiral α-arylpropionic acids and amides.
- Wu, Zhong-Liu,Li, Zu-Yi
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p. 3305 - 3312
(2007/10/03)
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- Chiral discrimination of 2-arylalkanoic acids by (1S,2R)-1-aminoindan-2-ol through the formation of a consistent columnar supramolecular hydrogen-bond network
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Enantiopure cis-1-aminoindan-2-ol was selected as a basic resolving agent for racemic 2-arylalkanoic acids on the basis that its rigid cis-conformation would favor the formation of a supramolecular hydrogen-bonded column, in which chiral discrimination of the racemic carboxylate would occur. It was found that this amino alcohol possesses high resolving efficiency for a variety of racemic acids; also, X-ray crystallographic analyses of the diastereomeric salts showed that a columnar hydrogen-bond network is formed in both the less- and more-soluble diastereomeric salts, as we had expected. A detailed study on the stabilising interactions suggested that there are two that play an important role: (i) hydrogen bonding between the ammonium and hydroxy groups and the acid carboxylate, which determines the formation of the columnar network and (ii) CH...π, which influences the herringbone packing of the aromatic groups, implying that it also plays some role in chiral discrimination.
- Kinbara, Kazushi,Kobayashi, Yuka,Saigo, Kazuhiko
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p. 111 - 119
(2007/10/03)
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- Enantioselective syntheses of 2-arylpropanoic acid non-steroidal antiinflammatory drugs and related compounds
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(S)-2-[4′-(2″-Methylpropyl)phenylpropanoic acid (ibuprofen) and (S)-2-(3′-benzoylphenyl)propanoic acid (ketoprofen) have been synthesised in high enantiomeric excess. Control of stereochemistry was achieved by a combination of Sharpless epoxidalion followed by catalytic hydrogenolysis of the introduced benzylic epoxide oxygen bond. Also, the coupling of organic compounds in the presence of palladium with enantiopure 2-(3-iodophenyl)propanoic and 2-(4-iodophenyl)propanoic acids, prepared by the methodology above, is a general method for the synthesis of optically active arylpropanoic acids.
- Hamon, David P.G.,Massy-Westropp, Ralph A.,Newton, Josephine L.
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p. 12645 - 12660
(2007/10/02)
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