Four new hydrazide derivatives containing benzothiazole T4a, T4b, T4c,and T4d were designed and synthesized successfully in a 4-step route in high yield.Structures of all samples were determined by 1H NMR, 13C NMR, HMBC, HSQC,and HRMS. All synthesized derivatives were tested for cytotoxic activity on the KBcell line. The results indicated moderate activity with an IC50 range of 18 - 52 µg/mL.Among them, compound T4a exhibited the highest activityFour new hydrazide derivatives containing benzothiazole T4a, T4b, T4c,and T4d were designed and synthesized successfully in a 4-step route in high yield.Structures of all samples were determined by 1H NMR, 13C NMR, HMBC, HSQC,and HRMS. All synthesized derivatives were tested for cytotoxic activity on the KBcell line. The results indicated moderate activity with an IC50 range of 18 - 52 µg/mL.Among them, compound T4a exhibited the highest activity