摘要:
The subject invention concerns a process for preparing a compound of formula (3) ##STR1## in enantio-enriched form, comprising reducing a compound of formula (4) ##STR2## using an asymmetric enantiospecific reductant, wherein A.sup.1 .dbd.A.sup.2 .dbd.H or A.sup.1, A.sup.2 .dbd.O; B.sup.1 .dbd.B.sup.2 .dbd.H or B.sup.1, B.sup.2 .dbd.O; Z.dbd.H, C.sub.1-20 alkyl or a precursor thereof, or a removable protecting group for nitrogen, e.g, acyl or alkyloxycarbonyl; Y.dbd.H or a substituent; R.sup.1 .dbd.C.sub.1-20 alkyl; and R is an optional, additional substituent.
摘要:
A process for the preparation of optically-enriched pipecolic acid as a salt with an optically-active acid, comprises asymmetric transformation of pipecolic acid, as a racemic mixture of a mixture enriched in the opposite enantiomer from that desired, with the optically-active acid in a solvent comprising an acid that causes racemisation, in the absence of aldehyde.
摘要:
A process for the racemisation of an optically-enriched piperidine-2-carboxanilide compound, comprises heating the compound in the presence of an alkanoic or arylalkanoic acid. A process for the asymmetric transformation of such a compound comprises heating the compound in the presence of an acid as defined above, a chiral acid resolving agent and an inert cosolvent.
摘要:
An optically-enrichedpiperidine-2-carboxanlidecompound, in which the piperidine is optionally N-alkylated, is racemized by heating the compound in an aqueous medium, provided that the medium includes an organic co-solvent if the compound is N-alkylated. This process is particularly valuable, in conjunction with a resolution process, for the manufacture of levobupivacaine.
摘要:
The subject invention pertains to a process for the resolution of etodolac comprising the use of the resolving agent glucamine or a N-(C.sub.1-4 alkyl)-glucamine. The subject invention also concerns a process for converting a single enantiomer of etodolac into the racemate. The method comprises forming all ester of the carboxylate function of the enantiomer and treating with an acid or base.