From family 3, only click conjugates 19, 22, 23 and 24 presented medium or low toxicity on the host cells. Adenine compound 22 exhibited a promising IC50 value of 0.108 µM, but also considerably impaired HFF viability (52%). Uracil and thymine click derivatives 23 and 24 had a lower impact on the host cells viability (64 and 85%) but presented IC50 values higher or comparable to that of pyrimethamine (0.426 and 0.357 µM).