摘要:
A process for preparing an optically-enriched chiral epoxide of formula I wherein R1, R2 and R3 are each independently selected from H, R, R—CO— and R—O—CO—, each R independently being substantially a hydrocarbon group of up to 20 carbon atoms, and X is an alkyl or cycloalkyl group of up to 10 carbon atoms, provided that —CO—X is not enolisable, which comprises the asymmetric epoxidation of a corresponding prochiral alkene of formula II R1R2C═CR3—CO—X (II) by reaction with an oxidant in the presence of a chiral catalyst. Many optically-enriched epoxides (I) are novel.
摘要:
A process for the preparation of lipolic acid (thioctic acid), or a derivative thereof, is one in which a 2-substituted cyclohexanone is transformed in an oxidation reaction to a lactone having formula (I), wherein X is a heteroatom substituent.
摘要:
The subject invention pertains to optically-enriched compounds of formula (1), wherein Ar is a C.sub.6-20 aryl group; and R.sup.1 and R.sup.2 are independently H, alkyl or aryl. The subject invention also pertains to method of preparing these compounds. The subject compounds can be prepared by reduction of the corresponding 1,4-dihydropyridine-3-aldehyde, e.g., using hydrogen an a catalyst. The aldehyde can be prepared by hydrolytic cleavage of an aminal obtainable by the reaction of 3-pyridinecarboxaldehyde and a chiral C-2 symmetric diamine, an then stereoselective introduction of the Ar and COOCHR.sup.1 R.sup.2 groups. ##STR1##
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.
摘要:
A process for the preparation of diols by a Lewis acid-catalysed aldehyde addition reaction on hydroxyalkynes followed by hydrogenation is described. The process provides a wide range of diols from simple, readily available starting materials. In particular the process is suitable for preparing chiral 1,4-diols suitable for the preparation of chiral phospholane ligands for use in asymmetric catalysis.
摘要:
A process is described for obtaining a single enantiomer from a racemic mixture of the bicyclic lactam 2-azabicyclo�2.2. 1! hept-5-en-one by seeding a supersaturated solution of the lactam and a solvent with a single enantiomer of the lactam.