4-硫胸苷/UVA(长波黑斑效应紫外线)辅助疗法为癌症治疗提供了新的途径，通过对胸苷进行修饰，得到对近紫外光敏感的药物，从而在紫外光的协同作用下达到治疗肿瘤细胞的作用。为了得到新型具有光学性质的4-硫胸苷类药物，传统使用三唑法和P₂S₅法，而本文采用了新试剂——Lawesson试剂，极大的缩短了反应时间，提高了产率，并用¹H-NMR及¹³C-NMR表征了产物结构。
4-Thiothymidine combined with UVA (light shading effect with long-wave ultraviolet) as a potentially novel therapy for cancer provides a new way, UVA-sensitive 4-thiothymidine was obtained through the study of the modification of thiothymidine at 4-position, and reached the role of treatment of tumor cells under the synergy of UVA. In order to obtain 4-Thiothymidine drugs with new optical properties, triazole and P₂S₅ are used in previously reported methods. In this study, Lawesson reagent was adopted to prepare 4-thiothymidine. Under the optimized conditions, the reaction time was significantly reduced and the yield increased. The structure of the product was characterized by ¹H-NMR and ¹³C-NMR.