An efficient method for the preparation of the antibiotic chloramphenicol [(+)-4] is described. Methyl (±)-threo-N-dichloroacetyl-ß-(4-nitrophenyl)serinate [(±)-threo-2], readily obtainable on a preparative laboratory scale, was enantioselectively hydrolyzed by Subtilisin. This enzymatic kinetic resolution gave the corresponding (2S,3R)-acid 3 and the unhydrolyzed (2R,2S)-ester (-)-threo-2 in high yield and high optical purity. Reduction of the (2S,3R)-acid 3 by borane-methyl sulfide complex gave chloramphenicol [(+)-4]. Reduction of the (2R,3S)-ester (-)-threo-2 by lithium aluminum hydride gave the enantiomer (-)-4 chloramphenicol.
描述了一种制备抗生素
氯霉素[(+)-4]的高效方法。通过Subtilisin进行酶催化动力学拆分,可以对易于在制备实验室规模上获得的甲基(±)-threo-N-二
氯乙酰基-β-(4-
硝基苯基)
丝氨酸酯[(±)-threo-2]进行对映选择性
水解。该酶催化动力学拆分以高产率和高光学纯度得到相应的(2S,3R)-酸3和未
水解的(2R,2S)-酯(-)-threo-2。通过
硼烷-甲
硫醚复合物对(2S,3R)-酸3进行还原反应得到
氯霉素[(+)-4]。
锂铝氢对(2R,3S)-酯(-)-threo-2进行还原反应得到对映体(-)-4
氯霉素。