Provided is a preparation method of a composition enriched in compound S p-1.Themethod performs isomer separation on a reaction product from the first step,and then performsa two-step chemical synthesis, so as to prepare a composition comprising high-puritycompound S p-1, wherein the HPLC purity of the single isomer S p-1 is 90% ormore. Providedis a composition enriched in compound S p-1. The composition has an inhibitoryeffect ontumor cell proliferation in vitro significantly higher than that of NUC-1031and compound R p-1.Also provided are the use of the composition, and a pharmaceutical compositioncomprisingthe composition and at least one pharmaceutically acceptable excipient.
