| 摘要 |
Process for the preparation of esters of N-protected proline, optionally substituted at the 3 and/or 4 positions. According to the process of the invention, an alpha-ester of glutamic acid, which may be laevorotatory, dextrorotatory or racemic, in the threo or erythro form or as a mixture of diastereoisomers, of formula: <IMAGE> in which R represents a hydrogen atom, a fluorine or chlorine atom or a C1-C6 alkyl radical optionally substituted with one or more fluorine or chlorine atoms or with the trifluoromethyl radical, R' represents a hydrogen atom or a C1-C6 alkyl radical optionally substituted with one or more fluorine or chlorine atoms, y represents an alkyl or aralkyl radical, X represents the groups generally used to protect the amine functional group of amino acids, is reacted with diborane or one of its complexes. It is possible to use the esters obtained directly in many applications, especially for forming peptides, or to convert them in order to obtain proline or its homologues.
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