| 摘要 |
The optically active compounds of formula I are useful for the preparation of optically active 3-aminopyrrolidine derivatives which are important building blocks for the production of useful products in the chemical, agricultural and in the pharmaceutical industry. In particular they are useful in the production of antibacterial substances for example of vinylpyrrolidinone-cephalosporin derivatives. The process may also be used for the preparation of N-protected L-asparagine by work up of the remaining aqueous layer. The present invention relates to a new process for the preparation of D-asparagine derivatives of formula I <CHEM> wherein R<1> is an amino protecting group and R<2> is an alkyl, a substituted alkyl or a group of formula A R<3)<OCH2CH2)n- A wherein R<3> is hydrogen or an lower alkyl group and n is 1, 2 or 3., which process comprises reacting a compound of formula II <CHEM> wherein R<1> and R<2> are as defined above, with a protease in an aqueous system at a pH of 6.0-7.5, preferably 6.0-7.0, together with an organic co-solvent and subsequent extraction of the enantiomeric pure product of formula I.
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