30339-30-1Relevant articles and documents
Resolution of 1-phenyl-2-(p-tolyl)ethylamine via diastereomeric salt formation
Pallavicini, Marco,Bolchi, Cristiano,Moroni, Barbara,Valoti, Ermanno,Piccolo, Oreste
, p. 2247 - 2251 (2003)
(S)-1-Phenyl-2-(p-tolyl)ethylamine (S)-1, used for the industrial scale resolution of chrysanthemic acids, was obtained via resolution of the racemate with the hemiphthalate of (S)-isopropylidene glycerol (R)-2. The maximum experimental efficiency [69% yield and >99% e.e. of (S)-1] was achieved by a simple precipitation of (S)-1·(R)-2 from the solution of the 1:1 diastereomeric salt mixture in 93/7 isopropanol/water at saturation of the more soluble (R)-1·(R)-2 salt. Such an experimental efficiency was consistent with 0.79 maximum theoretical resolvability, derived from the solubilities of the two diastereomeric salts, and with DSC data, which indicated that the (S)-1·(R)-2/(R)-1·(R)-2 system is a binary mixture exhibiting an eutectic with composition approximately corresponding to a 0.2 molar ratio of (S)-1·(R)-2.
PROCESS FOR PREPARING HYDROCINNAMIC ALDEHYDES IN ENANTIOPURE OR ENANTIOMERICALLY ENRICHED FORM
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Page/Page column 26-27, (2010/12/17)
A process is described for preparing hydrocinnamic aldehydes in enantiopure or enantiomerically enriched form of Formula I, in which R is isopropyl or tert-butyl and R' is hydrogen, or R and R' when taken together are a methylenedioxolyl group, comprising the following steps: a) reacting the hydrocinnamic aldehyde of Formula I with the alcohol of Formula Il in enantiopure or enantiomerically enriched form to give the crystallized hemiacetal of Formula III, in which R, R' have the same meaning as Formula I and (*) indicates a stereogenic centre in the absence of a solvent or in one or more aprotic solvents or mixtures thereof with apolar solvents; b) recovering the hydrocinnamic aldehyde of Formula I in enantiopure or enantiomerically enriched form from the crystallized hemiacetal of Formula III and the aldehyde of opposite configuration in enantiopure or enantiomerically enriched form from the hemiacetal crystallization mother liquors. The invention also concerns a process for preparing the alcohol of Formula Il to be introduced into step a).
Synthesis of enantiomerically pure amino-substituted fused bicyclic rings
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, (2008/06/13)
This invention describes various processes for synthesis and resolution of racemic amino-substituted fused bicyclic ring systems. One process utilizes selective hydrogenation of an amino-substituted fused bicyclic aromatic ring system. An alternative process prepares the racemic amino-substituted fused bicyclic ring system via nitrosation. In addition, the present invention describes the enzymatic resolution of a racemic mixture to produce the (R)- and (S)-forms of amino-substituted fused bicyclic rings as well as a racemization process to recycle the unpreferred enantioner. Further provided by this invention is an asymmetric synthesis of the (R)- or (S)-enantiomer of primary amino-substituted fused bicyclic ring systems.