OBJECTIVE Telmisartan is an angiotensin II receptor type 1 (AT1) antagonist with anticancer properties against solid and hematological cancer cell lines. Using telmisartan as a template, we developed alkylamine derivatives with reduced AT1 activity but increased anticancer activity. METHODS Synthesis of candidate compounds was carried out via hexafluorophosphate benzotriazole tetramethyl uronium coupling reaction, then their inhibition of cell proliferation was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and colony-formation assay was carried out on the lead candidate compound 8 Cell death via apoptosis or necrosis by compound 8 was determined by flow cytometry using annexin V and propidium iodide, tolerability dosing was carried out in ICR mice, and tumor-reduction properties were determined in an MDA-MB-231 xenograft model. RESULTS Some of the synthesized candidates exhibited good inhibition of cell proliferation with low micromolar half maximal effective concentrations in triple-negative breast cancer cell lines MDA-MB-231 and 4T1. Compound 8 exhibited lower affinity towards AT1 than parent telmisartan, inhibition of colony formation, and cell-cycle analysis revealed apoptosis as potentially important in causing cell death. In vivo evaluation with compound 8 indicated that it was well tolerated at high concentrations in healthy mice. Additionally, compound 8 showed higher growth inhibition in the MDA-MB-231 tumor xenograft mouse model compared to telmisartan. CONCLUSIONS Our study indicated that alkylamine derivatives of telmisartan exhibited good solubility and higher inhibition of cancer cell proliferation than telmisartan. Compound 8 was found to be a good lead compound, with potential for development as an anticancer agent.