| 摘要 |
A process for the preparation of racemic diol free base and/or acid addition salt and/or R- or S-diol free base and/or acid addition salt comprising a separation of an initial non-racemic mixture of R- and S-diol free base and/or acid addition salt with more than 50% of one of the enantiomers into a fraction being enriched with S-diol or R-diol free base and/or acid addition salt and a fraction comprising RS-diol free base and/or acid addition salt wherein the ratio of R-diol:S-diol is equal to 1:1 or closer to 1:1 than in the initial mixture of R- and S-diol characterized in that i) RS-diol free base and/or acid addition salt is precipitated from a solution of the initial non-racemic mixture of R- and S-diol free base and/or acid addition salt; or R- or S-diol free base and/or acid addition salt is dissolved into a solvent from the initial non-racemic mixture of R- and S-diol free base and/or acid addition salt in said solvent, leaving a residue comprising RS-diol free base and/or acid addition salt; ii) the residue/precipitate formed is separated from the final solution phase; iia) if the residue/precipitate is crystalline it is optionally recrystallised one or more times to form racemic diol; iib) if the residue/precipitate is not crystalline, steps i) and ii) are optionally repeated until a crystalline residue/precipitate is obtained and the crystalline residue/precipitate is optionally recrystallised one or more times to form racemic diol; iii) the final solution phase is optionally subjected to further purification and S-diol or R-diol free base and/or acid addition salt is isolated from the final solution phase; iv) the free bases of the diols obtained are optionally converted to acid addition salts thereof or acid addition salts of the diols obtained are optionally converted to other acid addition salts or acid addition salts of the diols obtained are optionally converted to the corresponding free bases. |
