申请人:Rhodia Chirex, Inc.
公开号:US20020007090A1
公开(公告)日:2002-01-17
A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol, which is a useful intermediate in the synthesis of the widely used antibiotic Levofloxacin is provided. A process for the preparation of (R)-1-(2,3-difluoro-6-nitrophenoxy)-2-trimethylsiloxypropane is also described. The process includes the ring opening of (R)-propylene oxide with 2,3-difluoro-6-nitrophenyl trimethylsilyl ether in the presence of an optically active Co(salen) catalyst. The trimethylsilyl group of the reactant is transferred to the product aryloxy alcohol, which serves to protect the secondary alcohol in situ. Upon isolation, the trimethylsilyl group is removed and the resulting regioisomeric mixture purified to yield the desired (R)-1-(2,3-difluoro-6-nitrophenoxy)-propan-2-ol in high purity and yield.
提供了一种制备(R)-1-(2,3-二氟-6-硝基苯氧基)-丙二醇的方法,该化合物是广泛使用的抗生素左氧氟沙星的合成中间体。还描述了制备(R)-1-(2,3-二氟-6-硝基苯氧基)-2-三甲基硅氧基丙烷的方法。该过程包括在手性Co(salen)催化剂存在下,用2,3-二氟-6-硝基苯基三甲基硅醚开环(R)-环氧丙烷。反应物的三甲基硅基团转移到产物芳氧基醇中,起到原位保护次级醇的作用。在分离后,去除三甲基硅基团并纯化所得的区域异构体混合物,得到高纯度和高产率的(R)-1-(2,3-二氟-6-硝基苯氧基)-丙二醇。