Substituted N-aminothioglycolurils containing thiosemicarbazone moiety and their cytotoxic activity in vitro

A library of hybrid molecules bearing thioglycoluril and (hetero)aromatic aldehyde thiosemicarbazone moieties was synthesized via a tandem hydrazone formation—ring contraction reaction of 5,7-dialkyl-3-thioxoperhydroimidazo[4,5-e]-1,2,4-triazin-6-ones with (hetero)aromatic aldehydes. All synthesized compounds were tested for their cytotoxic activity against rhabdomyosarcoma, A549, and MS human cancer cell lines by MTT-assay. Among the derivatives, (E)-4-benzylideneamino-1,3-dimethyl-5-thioxohexahydroimidazo[4,5-d]imidazol-2(1H)-one 1f was found to have the most marked antiproliferative activity toward the tested cell lines (1f: IC$$_{50}= 20.6,$$50=20.6, 23.7, and 6.4 $$\upmu $$μM, respectively). The IC$$_{50}$$50 value of thioglycoluril 1f against normal human embryonic kidney cells HEK293 was 72.5 $$\upmu $$μM, which appeared to be 3–11-fold higher than IC$$_{50}$$50 values of 1f against human cancer cells.