Asymmetric catalytichydrogenations of the entitled compounds were carried out over palladium on charcoal in various solvents to afford N-[(S)-lactoyl]-(S)-proline esters with a d.e.(=diastereoisomeric excess) of up to 59%. The stereochemistry of the catalytichydrogenation was explained by the “chelation mechanism.” And the effects of temperature and bulkiness of the ester groups on the asymmetric
Novel complex amido and imido derivatives of carboxyalkyl peptides
申请人:——
公开号:US04766110A1
公开(公告)日:1988-08-23
Novel inhibitors of angiotensin converting enzyme are disclosed which have the general formula ##STR1## wherein R.sub.1 and/or R.sub.3 form complex amides and imides thereof, R.sub.4 and R.sub.5 form with --N--C-- a 4-6 membered ring structure as described and the other R substituents are selected from a variety of disclosed groups.
N-Hydroxy dipeptides are readily synthesized by reduction of the corresponding oximes. The two diastereomers obtained are easily separated by flash chromatography. They can be coupled with a third amino acid moiety - without protection of the hydroxyl group - to give N-hydroxy tripeptides.