- Building blocks for the preparation of enantiomerically pure drugs containing a phenylalkylamine moiety
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The enantiomers of chiral drugs may exhibit distinctly different pharmacokinetic and pharmacodynamic properties. Thus, the application of pure enantiomers is desirable in most cases. Therefore, it is neccessary to know which enantiomer is the more advantageous one and to work out an economical large scale synthesis of this pure enantiomer. Biocatalytic transformations of prochiral compounds provide an easy and efficient access to chiral, non racemic compounds. Therefore, we fixed upon microbial reductions of carbonyl compounds as the key steps in the preparation of enantiomerically pure building blocks.
- Bracher,Litz
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p. 591 - 593
(2007/10/02)
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- ASYMMETRIC DIELS-ALDER REACTION CATALYSED BY SOME CHIRAL LEWIS ACIDS
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Diels-Alder reaction between cyclopentadiene and various dienophiles (mainly methacrolein) at -78 deg C was catalysed by various chiral aluminium alcoholates.The catalysts were prepared by reaction of EtAlCl2 with several families of diol (or their monoet
- Rebiere, F.,Riant, O.,Kagan, H.B.
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p. 199 - 214
(2007/10/02)
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- Regio- and Enantio-selective Reduction of α,γ-Diketones by Fermenting Baker's Yeast
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Reduction of various numbers of 2,4 alkanediones by fermenting baker's yeast has been found to be highly regio- and enantioselective, resulting in the formation of 2-hydroxy-4-alkanones.In some cases, optical purities of the products exceeded over 99percent as determined by HPLC analysis of MTPA esters.The highest yield was obtained when the reaction was carried out at pH 8 with low substrate concentration.As the representative β-hydroxyketones, the absolute configuration of (+)-2-hydroxy-4-octanone (2d) and (+)-3-hydroxy-1-phenyl-1-butanone (2h) was unambiguously determined to be (S) by comparing the specific rotation of diol derivatives with those of authentic specimens.
- Ohta, Hiromichi,Ozaki, Kazuhiko,Tsuchihashi, Gen-ichi
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p. 2499 - 2502
(2007/10/02)
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- Electron transfer reactions from alkali metal surfaces to (+/-) and (S)-(-)-1,3-dimethoxy-1,1-diphenylbutane. Studies on 1,3-elimination
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The 1,3-elimination of methoxide by carbanions generated from the reaction of (+/-)-1,3-dimethoxy-1,1-diphenylbutane with the alkali metals, lithium, sodium, and potassium, in various solvents was studied to determine the significance of cation-methoxyl c
- Walborsky, Harry M.,Murari, Martha Pass
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p. 2464 - 2470
(2007/10/02)
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