Method for preparing penicillin-G-1-(S)-oxide

The invention relates to a method for preparing penicillin-G-1-(S)-oxide. In the method, penicillin G is used as a raw material, and the oxidization of the penicillin G and the crystallization of penicillin-G-1-(S)-oxide which is the oxidization product of the penicillin G are performed at the same time. A penicillin-G-1-(S)-oxide crystal product is obtained by directly adding an oxidant into penicillin G organic phase solution, reacting and crystallizing, the oxidization reaction and the crystallization are performed at the same time, and the crystal product directly precipitates in organic solution. Compared with the conventional direct oxidization process, the method has the advantages that: the operation flow is simplified considerably; the operation is simple and convenient; the labor intensity is lowered; and the production period is shortened obviously. The process of extracting the penicillin G from the organic phase back to a water phase and the process of regulating pH value with diluted acid and crystallizing are saved, so the consumption of waster resources is reduced greatly, the discharge of waste acid liquor is reduced, and the problem of environmental pollution is alleviated obviously. The high-performance liquid chromatography (HPLC) content of the product reaches over 99.0 percent, and the weight yield of products with a main particle size over 30 mu m is over 90 percent.