| 摘要 |
Stereoconservative method for preparation of an (R)- or (S)-isomer of the compound of the formula I with at least 95% optical purity <CHEM> wherein R<1> is a hydrogen atom, a saturated or unsaturated lower alkyl group, a cycloalkyl group, or a group (CH2)m Ph wherein m is O-3 and Ph is a substituted or unsubstituted phenyl group including l) O,N-dialkylation, directly or stepwise of (R)- or (S)-proline 2) aminolysis 3) reduction to formation of the (R)- or (S)-isomer of the compound of the formula I, and new intermediates II and III in optical active form obtained by the reaction steps above and wherein R<2> is defined as R<1> above. <CHEM> h |
