申请人:Shell Internationale Research Maatschappij B.V.
公开号:US05164519A1
公开(公告)日:1992-11-17
A process is disclosed for preparing a 2,2-R.sub.1, R.sub.2 -1,3-dioxolane-4-carboxylic acid or salt thereof rich in either the R or S enantiomer which process comprises a) preparing a solution which contains a non-racemic mixture of R and S enantiomer of a carboxylate of the formula ##STR1## and M.sup.n+ ions, wherein R.sub.1 and R.sub.2 are each, independently, H or an unsubstituted or substituted alkyl group, or R.sub.1 and R.sub.2, together with the carbon atom to which they are attached, form an unsubstituted or substituted carbocyclic ring, and M is an alkali metal, an alkaline earth metal, a group IIb metal, boron, or an ammonium, di- or tri-alkanolammonium ion having 2 or 3 carbon atoms or a tetra C.sub.1 -C.sub.16 alkyl ammonium ion, and n is the valency of M; b) reducing the solubility of the M.sup.n+ salt of compound (I); and c) separating the resulting crystals from the mother liquor.
公开了一种制备2,2-R.sub.1,R.sub.2-1,3-二氧兰-4-羧酸或其盐的过程,其中该过程包括:a)制备含有式的羧酸盐的R和S对映体的非外消旋混合物及M.sup.n+离子的溶液:##STR1## 其中R.sub.1和R.sub.2各自独立地为H或未取代或取代的烷基,或R.sub.1和R.sub.2与它们所连接的碳原子一起形成未取代或取代的碳环;M是碱金属,碱土金属,IIb族金属,硼或具有2或3个碳原子的铵,二元或三元醇铵离子或四个C.sub.1-C.sub.16烷基铵离子,n是M的价;b)降低化合物(I)的M.sup.n+盐的溶解度;c)从母液中分离出所得的晶体。