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2005
Biochemical syntheses
O 0035
Realization of the Synthesis of α,α-Disubstituted Carbamylacetates and Cyanoby Either Enzymatic or Chemical Functional Group Transformation,
09- 026 acetates
Depending upon the Substrate Specificity of Rhodococcus Amidase. — The substrate specificity and enantioselectivity of nitrile hydratase and amidase of Rhodococcus rhodochrous is studied in the hydrolysis reaction of α,α-disubstituted malononitriles (I). The reaction provides a wide range of carbamylacetate derivatives (II) in moderate to high stereoselectivities. It is shown that the reaction proceeds via the diamide
intermediates. This method finds successful application in the synthesis of compound
(IX), a synthetic precursor of (S)-α-methyldopa. The presented method is sensitive to
steric hindrance [cf. (IV)] as well as to the presence of an α-fluorine substituent. Thus,
discouraging results are achieved in the enzyme-catalyzed hydrolysis of malononitrile
(X), and the desired NMR derivatizing agent (XIV) is prepared in a different way in
racemic form only. — (YOKOYAMA, M.; KASHIWAGI, M.; IWASAKI, M.;
FUHSHUKU, K.-I.; OHTA, H.; SUGAI*, T.; Tetrahedron: Asymmetry 15 (2004) 18,
2817-2820; Dep. Chem., Keio Univ., Kohoku, Yokohama 223, Japan; Eng.) —
Mischke
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